Interface and Morphology Engineered Amorphous Si for Ultrafast Electrochemical Lithium Storage.

Ultrafast high-capacity lithium-ion batteries are extremely desirable for portable electronic devices, where Si is the most promising alternative to the conventional graphite anode due to its very high theoretical capacity. However, the low electronic conductivity and poor Li-diffusivity limit its rate capability. Moreover, high volume expansion/contraction upon Li-intake/uptake causes severe pulverization of the electrode, leading to drastic capacity fading. Here, interface and morphology-engineered amorphous Si matrix is being reported utilizing a few-layer vertical graphene (VG) buffer layer to retain high capacity at both slow and fast (dis)charging rates. The flexible mechanical support of VG due to the van-der-Waals interaction between the graphene layers, the weak adhesion between Si and graphene, and the highly porous geometry mitigated stress, while the three-dimensional mass loading enhanced specific capacity. Additionally, the high electronic conductivity of VG boosted rate-capability, resulting in a reversible gravimetric capacity of ≈1270 mAh g-1 (areal capacity of ≈37 µAh cm-2 ) even after 100 cycles at an ultrafast cycling rate of 20C, which provides a fascinating way for conductivity and stress management to obtain high-performance storage devices.

Polarization-Resolved Position-Sensitive Self-Powered Binary Photodetection in Multilayer Janus CrSBr.

Recent progress in polarization-resolved photodetection based on low-symmetry 2D materials has formed the basis of cutting-edge optoelectronic devices, including quantum optical communication, 3D image processing, and sensing applications. Here, we report an optical polarization-resolving photodetector (PD) fabricated from multilayer semiconducting CrSBr single crystals with high structural anisotropy. We have demonstrated self-powered photodetection due to the formation of Schottky junctions at the Au-CrSBr interfaces, which also caused the photocurrent to display a position-sensitive and binary nature. The self-biased CrSBr PD showed a photoresponsivity of ∼0.26 mA/W with a detectivity of 3.4 × 108 Jones at 514 nm excitation of fluency (0.42 mW/cm2) under ambient conditions. The optical polarization-induced photoresponse exhibits a large dichroic ratio of 3.4, while the polarization is set along the a- and the b-axes of single-crystalline CrSBr. The PD also showed excellent stability, retaining >95% of the initial photoresponsivity in ambient conditions for more than five months without encapsulation. Thus, we demonstrate CrSBr as a fascinating material for ultralow-powered optical polarization-resolving optoelectronic devices for cutting-edge technology.

Complex Strain Scapes in Reconstructed Transition-Metal Dichalcogenide Moiré Superlattices.

We investigate the intrinsic strain associated with the coupling of twisted MoS2/MoSe2 heterobilayers by combining experiments and molecular dynamics simulations. Our study reveals that small twist angles (between 0 and 2°) give rise to considerable atomic reconstructions, large moiré periodicities, and high levels of local strain (with an average value of ∼1%). Moreover, the formation of moiré superlattices is assisted by specific reconstructions of stacking domains. This process leads to a complex strain distribution characterized by a combined deformation state of uniaxial, biaxial, and shear components. Lattice reconstruction is hindered with larger twist angles (>10°) that produce moiré patterns of small periodicity and negligible strains. Polarization-dependent Raman experiments also evidence the presence of an intricate strain distribution in heterobilayers with near-0° twist angles through the splitting of the E2g1 mode of the top (MoS2) layer due to atomic reconstruction. Detailed analyses of moiré patterns measured by AFM unveil varying degrees of anisotropy in the moiré superlattices due to the heterostrain induced during the stacking of monolayers.

Chiral Light Emission from a Hybrid Magnetic Molecule-Monolayer Transition Metal Dichalcogenide Heterostructure.

Hybrid layered materials assembled from atomically thin crystals and small molecules bring great promises in pushing the current information and quantum technologies beyond the frontiers. We demonstrate here a class of layered valley-spin hybrid (VSH) materials composed of a monolayer two-dimensional (2D) semiconductor and double-decker single molecule magnets (SMMs). We have materialized a VSH prototype by thermal evaporation of terbium bis-phthalocyanine onto a MoS2 monolayer and revealed its composition and stability by both microscopic and spectroscopic probes. The interaction of the VSH components gives rise to the intersystem crossing of the photogenerated carriers and moderate p-doping of the MoS2 monolayer, as corroborated by the density functional theory calculations. We further explored the valley contrast by helicity-resolved photoluminescence (PL) microspectroscopy carried out down to liquid helium temperatures and in the presence of the external magnetic field. The most striking feature of the VSH is the enhanced A exciton-related valley emission observed at the out-of-resonance condition at room temperature, which we elucidated by the proposed nonradiative energy drain transfer mechanism. Our study thus demonstrates the experimental feasibility and great promises of the ultrathin VSH materials with chiral light emission, operable by physical fields for emerging opto-spintronic, valleytronic, and quantum information concepts.

Isotope Engineered Fluorinated Single and Bilayer Graphene: Insights into Fluorination Selectivity, Stability, and Defect Passivation.

Tailoring the physicochemical properties of graphene through functionalization remains a major interest for next-generation technological applications. However, defect formation due to functionalization greatly endangers the intrinsic properties of graphene, which remains a serious concern. Despite numerous attempts to address this issue, a comprehensive analysis has not been conducted. This work reports a two-step fluorination process to stabilize the fluorinated graphene and obtain control over the fluorination-induced defects in graphene layers. The structural, electronic and isotope-mass-sensitive spectroscopic characterization unveils several not-yet-resolved facts, such as fluorination sites and CF bond stability in partially-fluorinated graphene (F-SLG). The stability of fluorine has been correlated to fluorine co-shared between two graphene layers in fluorinated-bilayer-graphene (F-BLG). The desorption energy of co-shared fluorine is an order of magnitude higher than the CF bond energy in F-SLG due to the electrostatic interaction and the inhibition of defluorination in the F-BLG. Additionally, F-BLG exhibits enhanced light-matter interaction, which has been utilized to design a proof-of-concept field-effect phototransistor that produces high photocurrent response at a time <200 µs. Thus, the study paves a new avenue for the in-depth understanding and practical utilization of fluorinated graphenic carbon.

Lacrimal Sac Tumors: A Case Series.

Objective: The aim of the study was to describe the clinical presentation, management strategies, and outcomes in a case series of primary lacrimal sac tumors. Methods: This retrospective study was conducted in Sheikh Fajilatunnessa Mujib Eye Hospital and Training Institute, Bangladesh, from July 1 to December 31, 2020, and included all patients who were evaluated, treated, and followed up for at least 6 months from January 2013 to October 2020. One patient developed a recurrence of the adenocarcinoma of the lacrimal sac after 1 year of primary treatment. Patients' demographic data were analyzed and reviewed from published articles on lacrimal sac tumors. We assessed patients clinically, followed by radiological evaluation. We also analyzed the biopsy technique, treatment modality, and recurrence. An oncologist reviewed all patients to prepare a plan for adjuvant treatment. Results: Ten patients with lacrimal sac tumors were included in this study. Swelling in the medial canthal region was the most common presenting feature (100%), followed by epiphora (60%) and pain (30%). Open biopsy was preferred over fine-needle aspiration biopsy. Incisional biopsy or complete excisional biopsy was performed for all suspected malignancies. Malignant tumors were found in 7 (70%) cases, and benign tumors in 3 (30%) cases. Non-Hodgkin's lymphoma (NHL) (40%) was the most common malignant lacrimal sac tumor. Mucosa-associated lymphoid tissue lymphoma was 75%, and diffuse large B-cell lymphoma was 25% among the cases of NHL. Patients with epithelial malignancy were treated with external beam radiation therapy, while NHL patients were treated with chemotherapy (CHOP regimen). Recurrence was noted in 1 case (10%) of epithelial malignancy after 1 year of treatment. Conclusion: Successful management of lacrimal sac tumors requires a high index of suspicion, as these are fatal tumors, often misdiagnosed as dacryocystitis. Nonepithelial malignancies are more predominant than epithelial malignancies, and hematolymphoid tumors are most frequent.

Clinicopathological Analysis and Surgical Outcome of Eyelid Malignancies: A Study of 332 Cases.

BACKGROUND: Eyelid tumours are common in our ophthalmic practice. Malignancy cases account only for one-fourth of all eyelid tumours. The most aggressive eyelid malignancy is sebaceous gland carcinoma, but its occurrences are rare in western countries. We found sebaceous gland carcinoma is as common as basal cell carcinoma in our clinical practices. Hence, it is essential to build awareness about the more aggressive eyelid malignancies to reduce morbidity and mortality. AIM: To assess the relative frequency of eyelid malignancies in the Bangladesh population, state their clinical features and outcome of management strategies and build awareness about the more aggressive eyelid malignancies to reduce morbidity and mortality. METHODS: This was a retrospective case series study of 332 patients in Bangladesh. This study analyzed all the recorded data of the histologically proven primary eyelid malignancies and followed them up for at least six months from 2014 to 2019 (6 years). All patients were managed by surgical excision with tumor-free margins verified on histopathology, either the frozen section or excision biopsy with 2-3 mm microscopic view of normal tissue followed by eyelid reconstruction. Computer-based statistical software SPSS was used for the analysis, and an appropriate test of significance (chi-square) was used for the statistical analysis. RESULTS: Sebaceous gland carcinoma (SGC) was the highest in occurrence, at 42%, followed by 38% basal cell carcinoma (BCC), 18% squamous cell carcinoma (SqCC), and 02% malignant melanoma (MM). The mean age at presentation of SGC, BCC, SqCC, and MM were 57.41 years, 62.56 years, 64.73 years, and 59.28 years, respectively. Female (59%) was slightly more preponderance over the male (41%) for SGC than other malignancies. Pigmentation was associated with malignant melanoma (100%) and BCC (81%). Statistically, a significant difference was found between eyelid malignancies, including location, size, pigmentation, recurrence, and invasiveness. The recurrence rate was low lower in the patients who underwent frozen section biopsy (3%) for margin clearance than those who underwent excision biopsy (21.5%) in the follow-up time. Conjunctival map biopsy (8%) was performed as an essential tool for excluding the pagetoid spread of SGC. A new reconstruction method named triangular-shaped musculocutaneous tail flap was performed in 33 (11%) patients to reconstruct the moderate eyelid defect following local resection. CONCLUSION: Sebaceous gland carcinoma (SGC) was the highest occurrence found to be the highest occurrence among all eyelid malignancies in Bangladesh. SGC is more aggressive and the recurrence rate was higher than BCC and SqCC.

Highly sensitive broadband binary photoresponse in gateless epitaxial graphene on 4H-SiC.

Due to weak light-matter interaction, standard chemical vapor deposition (CVD)/exfoliated single-layer graphene-based photodetectors show low photoresponsivity (on the order of mA/W). However, epitaxial graphene (EG) offers a more viable approach for obtaining devices with good photoresponsivity. EG on 4H-SiC also hosts an interfacial buffer layer (IBL), which is the source of electron carriers applicable to quantum optoelectronic devices. We utilize these properties to demonstrate a gate-free, planar EG/4H-SiC-based device that enables us to observe the positive photoresponse for (405-532) nm and negative photoresponse for (632-980) nm laser excitation. The broadband binary photoresponse mainly originates from the energy band alignment of the IBL/EG interface and the highly sensitive work function of the EG. We find that the photoresponsivity of the device is > 10 A/W under 405 nm of power density 7.96 mW/cm2 at 1 V applied bias, which is three orders of magnitude greater than the obtained values of CVD/exfoliated graphene and higher than the required value for practical applications. These results path the way for selective light-triggered logic devices based on EG and can open a new window for broadband photodetection.

Ultralow Threshold Cavity-Free Laser Induced by Total Internal Reflection.

Total internal reflection is one of the most important phenomena when a propagated wave strikes a medium boundary, which possesses a wide range of applications spanning from optical communication to a fluorescence microscope. It has also been widely used to demonstrate conventional laser actions with resonant cavities. Recently, cavity-free stimulated emission of radiation has attracted great attention in disordered media because of several exciting physical phenomena, ranging from Anderson localization of light to speckle-free imaging. However, unlike conventional laser systems, the total internal reflection has never been implemented in the study of laser actions derived from randomly distributed media. Herein, we demonstrate an ultra-low threshold cavity-free laser system using air bubbles as scattering centers in which the total internal reflection from the surface of air bubbles can greatly reduce the leakage of the scattered beam energy and then enhance light amplification within a coherent closed loop. Our approach provides an excellent alternative for the manipulation of optical energy flow to achieve ultra-low threshold cavity-free laser systems, which should be very useful for the development of high performance optoelectronic devices.

Towards the evaluation of defects in MoS2 using cryogenic photoluminescence spectroscopy.

Characterization of the type and density of defects in two-dimensional (2D) transition metal dichalcogenides (TMDs) is important as the nature of these defects strongly influences the electronic and optical properties of the material, especially its photoluminescence (PL). Defect characterization is not as straightforward as it is for graphene films, where the D and D' Raman scattering modes easily indicate the density and type of defects in the graphene layer. Thus, in addition to the Raman scattering analysis, other spectroscopic techniques are necessary to perform detailed characterization of atomically thin TMD layers. We demonstrate that PL spectroscopy performed at liquid helium temperatures reveals the key fingerprints of defects in TMDs and hence provides valuable information about their origin and concentration. In our study, we address defects in chemical vapor deposition (CVD)-grown MoS2 monolayers. A significant difference is observed between the as-grown monolayers compared with the CVD-grown monolayers transferred onto a Si/SiO2 substrate, which contain extra defects due to the transfer process. We demonstrate that the temperature-dependent Raman and PL micro-spectroscopy techniques enable disentangling the contributions and locations of various defect types in TMD systems.

Graphene Sandwich Stable Perovskite Quantum-Dot Light-Emissive Ultrasensitive and Ultrafast Broadband Vertical Phototransistors.

Dual-functional devices that can simultaneously detect light and emit light have a tremendous appeal for multiple applications, including displays, sensors, defense, and high-speed optical communication. Despite the tremendous efforts of scientists, the progress of integration of a phototransistor, where the built-in electric field separates the photogenerated excitons, and a light-emitting diode, where the radiative recombination can be enhanced by band offset, into a single device remains a challenge. Combining the superior properties of perovskite quantum dots (PQDs) and graphene, here we report a light-emissive, ultrasensitive, ultrafast, and broadband vertical phototransistor that can simultaneously act as an efficient photodetector and light emitter within a single device. The estimated value of the external quantum efficiency of the vertical phototransistor is ∼1.2 × 1010% with a photoresponsivity of >109 A W-1 and a response time of <50 µs, which exceed all the presently reported vertical phototransistor devices. We also demonstrate that the modulation of the Dirac point of graphene efficiently tunes both amplitude and polarity of the photocurrent. The device exhibits a green emission having a quantum efficiency of 5.6%. The moisture-insensitive and environmentally stable, light-emissive, ultrafast, and ultrasensitive broadband phototransistor creates a useful route for dual-functional optoelectronic devices.

Self-Healing Nanophotonics: Robust and Soft Random Lasers.

Self-healing technology promises a generation of innovation in cross-cutting subjects ranging from electronic skins, to wearable electronics, to point-of-care biomedical sensing modules. Recently, scientists have successfully pulled off significant advances in self-healing components including sensors, energy devices, transistors, and even integrated circuits. Lasers, one of the most important light sources, integrated with autonomous self-healability should be endowed with more functionalities and opportunities; however, the study of self-healing lasers is absent in all published reports. Here, the soft and self-healable random laser (SSRL) is presented. The SSRL can not only endure extreme external strain but also withstand several cutting/healing test cycles. Particularly, the damaged SSRL enables its functionality to be restored within just few minutes without the need of additional energy, chemical/electrical agents, or other healing stimuli, truly exhibiting a supple yet robust laser prototype. It is believed that SSRL can serve as a vital building block for next-generation laser technology as well as follow-on self-healing optoelectronics.

Ultrasensitive Gas Sensors Based on Vertical Graphene Nanowalls/SiC/Si Heterostructure.

Gas sensors, which play an important role in the safety of human life, cover a wide range of applications including intelligent systems and detection of harmful and toxic gases. It is known that graphene is an ideal and attractive candidate for gas sensing due to its high surface area and excellent mechanical, electrical, optical, and thermal properties. However, in order to fully realize its potential as a commercial gas sensor, demand for a graphene-based device of low-limit detection, high sensitivity, and fast response time needs to be met. Here, we demonstrate a metal/insulator/semiconductor (MIS) based gas sensor consisting of as-grown epitaxial graphene nanowalls (EGNWs)/silicon carbide (SiC)/silicon (Si) structure. The unique edge dominant three-dimensional (3D) EGNWs based MIS device achieved an extraordinarily low limit of detection (0.5 ppm) and unprecedented sensitivity (82 µA/ppm/cm2 for H2) with a fast response of shorter than 500 ms. These unique properties of our MIS device are attributed to the abundance of vertically oriented nanographitic edges and structural defects that act as extra-favorable adsorption sites and exhibit fast electron-transfer kinetics through the edges. Our experimental findings can pave the way for the realization of high-performance 3D graphene-based gas sensor devices.

Single-Molecule-Based Electroluminescent Device as Future White Light Source.

During the last two decades, spectacular development of light-emitting diodes (LEDs) has been achieved owing to their widespread application possibilities. However, traditional LEDs suffer from unavoidable energy loss because of the down conversion of photons, toxicity due to the involvement of rare-earth materials in their production, higher manufacturing cost, and reduced thermal stability that prevent them from all-inclusive applications. To address the existing challenges associated with current commercially available white LEDs, herein, we report a broad-band emission originating from an intrinsic lanthanide-free single-molecule-based LED. Self-assembly of a butterfly-shaped strontium-based compound {[Sr(H2btc)2(MeOH)(H2O)2]·2H2O} (1) was achieved through the reaction of Sr(NO3)2 with 1,2,3-benzenetricarboxylic acid hydrate (1,2,3-H3btc) under hydrothermal conditions. A white LED based on this single molecule exhibited a remarkable broad-band luminescence spectrum with Commission Internationale de l'Eclairage (CIE) coordinates at (0.33, 0.32) under 30 mA current injection. Such a broad luminescence spectrum can be attributed to the simultaneous existence of several emission lines originating from the intramolecular interactions within the structure. To further examine the nature of the observed transitions, density functional theory (DFT) calculations were carried out to explore the geometric and electronic properties of the complex. Our study thus paves the way toward a key step for developing a basic understanding and the development of high performance broad-band light-emitting devices with environment-friendly characteristics based on organic-inorganic supramolecular materials.

Nanoscale Core-Shell Hyperbolic Structures for Ultralow Threshold Laser Action: An Efficient Platform for the Enhancement of Optical Manipulation.

Plasmonic material has emerged with multifunctionalities for its remarkable tailoring light emission, reshaping density of states (DOS), and focusing subwavelength light. However, restricted by its propagation loss and narrowband resonance in nature, it is a challenge for plasmonic material to provide a broadband DOS to advance its application. Here, we develop a novel nanoscale core-shell hyperbolic structure that possesses a remarkable coupling effect inside the multishell nanoscale composite owing to a higher DOS and a longer time of collective oscillations of the electrons than the plasmonic-based pure-metal nanoparticles. Subsequently, a giant localized electromagnetic wave of surface plasmon resonance is formed at the surface, causing pronounced out-coupling effect. Specifically, the nanoscale core-shell hyperbolic structure confines the energy well without being decayed, reducing the propagation loss and then achieving an unprecedented stimulated emission (random lasing action by dye molecule) with a record ultralow threshold (∼30 µJ/cm2). Besides, owing to the radial symmetry of the nanoscale core-shell hyperbolic structure, the excitation of high wavevector modes and induced additional DOS are easily accessible. We believe that the nanoscale core-shell hyperbolic structure paves a way to enlarge the development of plasmonic-based applications, such as high optoelectronic conversion efficiency of solar cells, great power extraction of light-emitting diodes, wide spectra photodetectors, carrying the emitter inside the core part as quantitative fluorescence microscopy and bioluminescence imaging system for in vivo and in vitro research on human body.

A Highly-Efficient Single Segment White Random Laser.

Production of multicolor or multiple wavelength lasers over the full visible-color spectrum from a single chip device has widespread applications, such as superbright solid-state lighting, color laser displays, light-based version of Wi-Fi (Li-Fi), and bioimaging, etc. However, designing such lasing devices remains a challenging issue owing to the material requirements for producing multicolor emissions and sophisticated design for producing laser action. Here we demonstrate a simple design and highly efficient single segment white random laser based on solution-processed NaYF4:Yb/Er/Tm@NaYF4:Eu core-shell nanoparticles assisted by Au/MoO3 multilayer hyperbolic meta-materials. The multicolor lasing emitted from core-shell nanoparticles covering the red, green, and blue, simultaneously, can be greatly enhanced by the high photonic density of states with a suitable design of hyperbolic meta-materials, which enables decreasing the energy consumption of photon propagation. As a result, the energy upconversion emission is enhanced by ∼50 times with a drastic reduction of the lasing threshold. The multiple scatterings arising from the inherent nature of the disordered nanoparticle matrix provide a convenient way for the formation of closed feedback loops, which is beneficial for the coherent laser action. The experimental results were supported by the electromagnetic simulations derived from the finite-difference time-domain (FDTD) method. The approach shown here can greatly simplify the design of laser structures with color-tunable emissions, which can be extended to many other material systems. Together with the characteristics of angle free laser action, our device provides a promising solution toward the realization of many laser-based practical applications.

Ultra-high performance flexible piezopotential gated In1-xSnxSe phototransistor.

Flexible optoelectronic devices facilitated by the piezotronic effect have important applications in the near future in many different fields ranging from solid-state lighting to biomedicine. Two-dimensional materials possessing extraordinary mechanical strength and semiconducting properties are essential for realizing nanopiezotronics and piezo-phototronics. Here, we report the first demonstration of piezo-phototronic properties in In1-xSnxSe flexible devices by applying systematic mechanical strain under photoexcitation. Interestingly, we discover that the dark current and photocurrent are increased by five times under a bending strain of 2.7% with a maximum photoresponsivity of 1037 AW-1. In addition, the device can act as a strain sensor with a strain sensitivity up to 206. Based on these values, the device outperforms the same class of devices in two-dimensional materials. The underlying mechanism responsible for the discovered behavior can be interpreted in terms of piezoelectric potential gating, allowing the device to perform like a phototransistor. The strain-induced gate voltage assists in the efficient separation of photogenerated charge carriers and enhances the mobility of In1-xSnxSe, resulting in good performance on a freeform surface. Thus, our multifunctional device is useful for the development of a variety of advanced applications and will help meet the demand of emerging technologies.

Transient and Flexible Hyperbolic Metamaterials on Freeform Surfaces.

Transient technology is deemed as a paramount breakthrough for its particular functionality that can be implemented at a specific time and then totally dissolved. Hyperbolic metamaterials (HMMs) with high wave-vector modes for negative refraction or with high photonic density of states to robustly enhance the quantum transformation efficiency represent one of the emerging key elements for generating not-yet realized optoelectronics devices. However, HMMs has not been explored for implementing in transient technology. Here we show the first attempt to integrate transient technology with HMMs, i.e., transient HMMs, composed of multilayers of water-soluble and bio-compatible polymer and metal. We demonstrate that our newly designed transient HMMs can also possess high-k modes and high photonic density of states, which enables to dramatically enhance the light emitter covered on top of HMMs. We show that these transient HMMs devices loss their functionalities after immersing into deionized water within 5 min. Moreover, when the transient HMMs are integrated with a flexible substrate, the device exhibits an excellent mechanical stability for more than 3000 bending cycles. We anticipate that the transient HMMs developed here can serve as a versatile platform to advance transient technology for a wide range of application, including solid state lighting, optical communication, and wearable optoelectronic devices, etc.

Low-Threshold Lasing from 2D Homologous Organic-Inorganic Hybrid Ruddlesden-Popper Perovskite Single Crystals.

Organic-inorganic hybrid two-dimensional (2D) perovskites have recently attracted great attention in optical and optoelectronic applications due to their inherent natural quantum-well structure. We report the growth of high-quality millimeter-sized single crystals belonging to homologous two-dimensional (2D) hybrid organic-inorganic Ruddelsden-Popper perovskites (RPPs) of (BA)2(MA) n-1Pb nI3 n+1 ( n = 1, 2, and 3) by a slow evaporation at a constant-temperature (SECT) solution-growth strategy. The as-grown 2D hybrid perovskite single crystals exhibit excellent crystallinity, phase purity, and spectral uniformity. Low-threshold lasing behaviors with different emission wavelengths at room temperature have been observed from the homologous 2D hybrid RPP single crystals. Our result demonstrates that solution-growth homologous organic-inorganic hybrid 2D perovskite single crystals open up a new window as a promising candidate for optical gain media.

A White Random Laser.

Random laser with intrinsically uncomplicated fabrication processes, high spectral radiance, angle-free emission, and conformal onto freeform surfaces is in principle ideal for a variety of applications, ranging from lighting to identification systems. In this work, a white random laser (White-RL) with high-purity and high-stability is designed, fabricated, and demonstrated via the cost-effective materials (e.g., organic laser dyes) and simple methods (e.g., all-solution process and self-assembled structures). Notably, the wavelength, linewidth, and intensity of White-RL are nearly isotropic, nevertheless hard to be achieved in any conventional laser systems. Dynamically fine-tuning colour over a broad visible range is also feasible by on-chip integration of three free-standing monochromatic laser films with selective pumping scheme and appropriate colour balance. With these schematics, White-RL shows great potential and high application values in high-brightness illumination, full-field imaging, full-colour displays, visible-colour communications, and medical biosensing.