NaH-promoted one-pot synthesis of 5-amidoimidazoles from arylamines, carbon disulfide and isocyanides.

A novel, convenient and efficient protocol to access functionalized 5-amidoimidazoles is developed via one-pot synthesis from readily available materials of arylamines, carbon disulfide and isocyanides. The transformation was realized at room temperature and provided 5-amidoimidazoles in moderate to good yields in the presence of NaH. In addition, control experiments indicated that the process might be achieved via the base-induced cyclization of activated methylene isocyanides with N,N-disubstituted thioureas that produced from the reaction of amines and carbon disulfide.

CuCl2·2H2O/TBHP mediated synthesis of ß-enaminones via coupling reaction of vinyl azides with aldehydes.

A facile and efficient oxidative functionalization of vinyl azides with aldehydes furnishing a diverse array of ß-acylated enaminones was developed. The cross coupling was accomplished in the presence of CuCl2·2H2O/TBHP and produced the desired ß-acylated enaminones in a (Z)-stereo-selective and atom-economic manner, which make this protocol particularly attractive. In the transformation, the new C-C and C-N bonds were formed via a one-pot strategy including the process of radical addition and recombination.

H2O2-mediated room temperature synthesis of 2-arylacetophenones from arylhydrazines and vinyl azides in water.

An environmentally benign, cost-efficient and practical methodology for the room temperature synthesis of 2-arylacetophenones in water has been discovered. The facile and efficient transformation involves the oxidative radical addition of arylhydrazines with α-aryl vinyl azides in the presence of H2O2 (as a radical initiator) and PEG-800 (as a phase-transfer catalyst). From the viewpoint of green chemistry and organic synthesis, the present protocol is of great significance because of using cheap, non-toxic and readily available starting materials and reagents as well as amenability to gram-scale synthesis, which provides an attractive strategy to access 2-arylacetophenones.

Photoexcited carrier dynamics in colloidal quantum dot solar cells: insights into individual quantum dots, quantum dot solid films and devices.

The certified power conversion efficiency (PCE) record of colloidal quantum dot solar cells (QDSCs) has considerably improved from below 4% to 16.6% in the last few years. However, the record PCE value of QDSCs is still substantially lower than the theoretical efficiency. So far, there have been several reviews on recent and significant achievements in QDSCs, but reviews on photoexcited carrier dynamics in QDSCs are scarce. The photovoltaic performances of QDSCs are still limited by the photovoltage, photocurrent and fill factor that are mainly determined by the photoexcited carrier dynamics, including carrier (or exciton) generation, carrier extraction or transfer, and the carrier recombination process, in the devices. In this review, the photoexcited carrier dynamics in the whole QDSCs, originating from individual quantum dots (QDs) to the entire device as well as the characterization methods used for analyzing the photoexcited carrier dynamics are summarized and discussed. The recent research including photoexcited multiple exciton generation (MEG), hot electron extraction, and carrier transfer between adjacent QDs, as well as carrier injection and recombination at each interface of QDSCs are discussed in detail herein. The influence of photoexcited carrier dynamics on the physiochemical properties of QDs and photovoltaic performances of QDSC devices is also discussed.

Near-Infrared Emission from Tin-Lead (Sn-Pb) Alloyed Perovskite Quantum Dots by Sodium Doping.

Phase-stable CsSnx Pb1-x I3 perovskite quantum dots (QDs) hold great promise for optoelectronic applications owing to their strong response in the near-infrared region. Unfortunately, optimal utilization of their potential is limited by the severe photoluminescence (PL) quenching, leading to extremely low quantum yields (QYs) of approximately 0.3 %. The ultra-low sodium (Na) doping presented herein is found to be effective in improving PL QYs of these alloyed QDs without alerting their favourable electronic structure. X-ray photoelectron spectroscopy (XPS) studies suggest the formation of a stronger chemical interaction between I- and Sn2+ ions upon Na doping, which potentially helps to stabilize Sn2+ and suppresses the formation of I vacancy defects. The optimized PL QY of the Na-doped QDs reaches up to around 28 %, almost two orders of magnitude enhancement compared with the pristine one.

Facile, eco-friendly, catalyst-free synthesis of polyfunctionalized quinoxalines.

A novel, facile and eco-friendly synthesis of quinoxalines from [Formula: see text] and 1,2-diamines was developed. An attractive feature of this protocol is that the desired products could be generated efficiently in water and without any catalyst, which is in accordance with the aim of green chemistry. A plausible mechanism has been proposed.

All-Inorganic CsPb1-x Gex I2 Br Perovskite with Enhanced Phase Stability and Photovoltaic Performance.

Compared with organic-inorganic perovskites, all-inorganic cesium-based perovskites without volatile organic compounds have gained extensive interests because of the high thermal stability. However, they have a problem on phase transition from cubic phase (active for photo-electric conversion) to orthorhombic phase (inactive for photo-electric conversion) at room temperature, which has hindered further progress. Herein, novel inorganic CsPb1-x Gex I2 Br perovskites were prepared in humid ambient atmosphere without a glovebox. The phase stability of the all-inorganic perovskite was effectively enhanced after germanium addition. In addition, the highest power conversion efficiency of 10.8 % with high open-circuit voltage (VOC ) of 1.27 V in a planar solar cell based on CsPb0.8 Ge0.2 I2 Br perovskite was achieved. Furthermore, the highest VOC up to 1.34 V was obtained by CsPb0.7 Ge0.3 I2 Br perovskite, which is a remarkable record in the field of all-inorganic perovskite solar cells. More importantly, all the photovoltaic parameters of CsPb0.8 Ge0.2 I2 Br perovskite solar cells showed nearly no decay after 7 h measurement in 50-60 % relative humidity without encapsulation.

Colloidal Synthesis of Air-Stable Alloyed CsSn1-xPbxI3 Perovskite Nanocrystals for Use in Solar Cells.

Organic-inorganic hybrid perovskite solar cells have demonstrated unprecedented high power conversion efficiencies in the past few years. Now, the universal instability of the perovskites has become the main barrier for this kind of solar cells to realize commercialization. This situation can be even worse for those tin-based perovskites, especially for CsSnI3, because upon exposure to ambient atmosphere the desired black orthorhombic phase CsSnI3 would promptly lose single crystallinity and degrade to the inactive yellow phase, followed by irreversible oxidation into metallic Cs2SnI6. By alloying CsSnI3 with CsPbI3, we herein report the synthesis of alloyed perovskite quantum dot (QD), CsSn1-xPbxI3, which not only can be phase-stable for months in purified colloidal solution but also remains intact even directly exposed to ambient air, far superior to both of its parent CsSnI3 and CsPbI3 QDs. Ultrafast transient absorption spectroscopy studies reveal that the photoexcited electrons in the alloyed QDs can be injected into TiO2 nanocrystals at a fast rate of 1.12 × 1011 s-1, which enables a high photocurrent generation in solar cells.

A novel quinazoline-based analog induces G2/M cell cycle arrest and apoptosis in human A549 lung cancer cells via a ROS-dependent mechanism.

6-amino-4-(4-phenoxyphenylethylamino)quinazoline (QNZ) is an excellent quinazoline-containing NF-κB inhibitor also acting as a novel anticancer agent. Considering both the medicinal significance of quinazoline scaffold and the tunable functionality of Michael acceptor-centric pharmacophores in the electrophilicity-based prooxidant strategy, we designed a novel QNZ-inspired electrophilic molecule QNZ-A by introducing a Michael acceptor unit at position-6 of quinazoline ring in QNZ. Our results identified QNZ-A as a promising selective cytotoxic agent against A549 cells. QNZ-A, by virtue of its Michael acceptor unit, induced reactive oxygen species (ROS) accumulation associated with collapse of the redox buffering system in A549 cells. This caused up-regulation of p53-inducible p21 and down-regulation of redox sensitive Cdc25C along with Cyclin B1/Cdk1, leading to a G2/M cell cycle arrest and final cell apoptosis. By contrast, QNZ-B, a reduction product of QNZ-A lacking the Michael acceptor unit failed to induce ROS generation and all these cell cycle-related events. In conclusion, this work provided a successful example of designing QNZ-directed anticancer agent by a ROS-promoting strategy and identified QNZ-A as a selective anticancer agent against A549 cells through G2/M cell cycle arrest and apoptosis via a ROS-dependent mechanism.

[Inversion of LAI by considering the hotspot effect for different geometrical wheat].

Aimed to deal with the limitation of canopy geometry to crop LAI inversion accuracy a new LAI inversion method for different geometrical winter wheat was proposed based on hotspot indices with field-measured experimental data. The present paper analyzed bidirectional reflectance characteristics of erective and loose varieties at red (680 nm) and NIR wavelengths (800 nm and 860 nm) and developed modified normalized difference between hotspot and dark-spot (MNDHD) and hotspot and dark-spot ratio index (HDRI) using hotspot and dark-spot index (HDS) and normalized difference between hotspot and dark-spot (NDHD) for reference. Combined indices were proposed in the form of the product between HDS, NDHD, MNDHD, HDRI and three ordinary vegetation indices NDVI, SR and EVI to inverse LAI for erective and loose wheat. The analysis results showed that LAI inversion accuracy of erective wheat Jing411 were 0.9431 and 0.9092 retrieved from the combined indices between NDVI and MNDHD and HDRI at 860 nm which were better than that of HDS and NDHD, the LAI inversion accuracy of loose wheat Zhongyou9507 were 0.9648 and 0.8956 retrieved from the combined indices between SR and HDRI and MNDHD at 800 nm which were also higher than that of HDS and NDHD. It was finally concluded that the combined indices between hotspot-signature indices and ordinary vegetation indices were feasible enough to inverse LAI for different crop geometrical wheat and multiangle remote sensing data was much more advantageous than perpendicular observation data to extract crop structural parameters.

Fabrication of two novel amino-functionalized and starch-coated CuFe2O4-modified magnetic biochar composites and their application in removing Pb2+ and Cd2+ from wastewater.

Novel magnetic biochar composites (SFeCu@SBCO and FeCu@SBCO-NH2) were fabricated by modifying oxidized sawdust biochar (SBCO) with Fe/Cu loading, starch-coating/amination, characterized (FTIR, XRD, BET, SEM-EDS and XPS) and applied in capturing Pb2+ and Cd2+ from wastewater. Adsorption experiments revealed that SFeCu@SBCO and FeCu@SBCO-NH2 exhibited extraordinary adsorption performance toward Pb2+/Cd2+ with the maximum adsorption capacity reaching 184.26/173.35 mg g-1 and 201.43/190.81 mg g-1, respectively, which were >5 times higher than those of SBC. The great increase in adsorption capacity of the two adsorbents was ascribed to the introduction of CuFe2O4 and starch/amino groups. Pb2+ and Cd2+ adsorption was an endothermic reaction controlled by monolayer chemisorption. Complexation and electrostatic attraction were the two predominant mechanisms. Besides, ion exchange together with physical adsorption also occurred during the adsorption. Additionally, the both adsorbents displayed favorable stability and reusability as well as desirable anti-interfering ability to other metal cations. Taken together, the both adsorbents could be utilized as reusable magnetic adsorbents with promising prospect in the effective remediation of Pb2+/Cd2+ contaminated water. The study not only contributed to the better understanding of biochar modification strategy and the application of modified biochar in heavy metals pollutants removal, but also realized resource utilization of biomass waste.

[Inversion of leaf area index during different growth stages in winter wheat].

Being orientated to the low prescion of crop leaf area index (LAI) inversion using the same spectral vegetation index during different crop growth stages, the present paper analyzed the precision of LAI inversion by employing NDVI(normalized difference vegetation index). Ten vegetation indices were chosen including six broad-band vegetation indices and four narrow-band vegetation indices responding to vegetation cover to inverse LAI in different growth stages. Several conclusions were drawn according to the analysis. The determinant coefficient (R2) and root mean square error (RMSE) between LAI inversion value and true value were 0.5585 and 0.3209 respectively during the whole growth duraton. The mSR (modified simple ratio index) index was appropriate to inverse of LAI during earlier growth stages (before jointing stage) in winter wheat. The R2 and RMSE between LAI inversion value and true value were 0.7287 and 0.2971 respectively. The SR (simple ratio index) index was suitable enough to inverse of LAI during medium growth stages (from joingting stagess to heading stages). The R2 and RMSE between LAI inversion value and true value were 0.6546 and 0.3061 respectively. The NDVI (normalized difference vegetation index) index was proven to be fine to inverse LAI during later growth stages(from heading stage to ripening stage). The R2 and RMSE between LAI inversion value and true value were 0.6794 and 0.3164 respectively. Therefore it was indicated that the results of LAI inversion was much better inverse of winter wheat LAI choosing different vegetation indices during differen growth stages for winter wheat according to the change of vegetation cover and canopy reflectance than merely with NDVI to inverse LAI in the whole growth stages. It was concluded that the precision of LAI inversion was significantly improved with segmented models based on different vegetation indices.

Meta-analysis of the effect of nitrification inhibitors on the abundance and community structure of N2O-related functional genes in agricultural soils.

Application of nitrification inhibitors (NIs) in agricultural systems is an important strategy to enhance fertilizer nitrogen use efficiency and mitigate soil nitrous oxide (N2O) emissions. Here, we conducted a global meta-analysis of 88 published studies to assess the response of N2O-related functional gene and transcript abundances, and community structure to NIs application. Application of NIs significantly reduced the abundance of ammonia-oxidizing bacteria ammonia monooxygenase (AOB amoA) genes, AOB amoA transcript and nitrite reductase (nirS and nirK) genes. The effectiveness of NIs on reducing the AOB amoA abundance was influenced by N form, soil texture, soil pH and the experimental type (field vs. laboratory). Specifically, NIs were more effective when a mixed inorganic and organic N source was applied to a medium-textured soils. The NIs effectiveness increased with increasing soil pH. The response of AOB amoA abundance to NIs application was not affected by NI type, N rate, soil moisture, soil temperature and soil organic carbon (SOC). The inhibitory effect of NIs on nirS abundance increased with increasing soil temperature. NIs decreased soil nitrifying enzyme activity (NEA) and denitrifying enzyme activity (DEA) by 34.5 % and 27.0 %, respectively, leading to an overall 63.6 % reduction of N2O emissions. Soil NEA correlated positively with the abundance and community structure of AOB amoA but not with AOA amoA. Decrease in DEA with NIs application coincided with the decreasing nirS and nirK abundances. This global-scale assessment demonstrates that the effectiveness of NIs in reducing N2O emissions was attributed to the inhibiting effects on AOB amoA, nirS and nirK genes. Our findings highlight that NIs' inhibition effects on bacterial ammonia-oxidizing community and the encode enzymes in transformation of nitrite to nitric oxide are the main mechanisms for mitigation of N fertilizer-induced N2O emissions.

Association of 3D-CRT and IMRT accelerated hyperfractionated radiotherapy with local control rate and 5-year survival in esophageal squamous cell carcinoma patients.

OBJECTIVES: This retrospective study examined the relevance and prognostic factors of whole-course conformal radiotherapy (CRT) and late-course accelerated hyperfractionation radiotherapy (LCAFRT) for esophageal squamous cell carcinoma (ESCC). METHODS: A total of 110 patients with ESCC received whole-course CRT and LCAFRT between May 2004 and January 2015. All patients received conventional CRT of 2 Gy per day, up to 30-40 Gy, followed by LCAFRT using reduced fields at 1.5 Gy/fraction twice a day, up to 24-39 Gy, for a total dose of 60-69 Gy. RESULTS: The median follow-up was 85 months. The whole groups 1-, 3-, and 5-year survival rates were 81.8%, 46.4%, and 41.8%, respectively. The local control rates for the whole group at 1, 3, and 5 years were 82.7%, 70.0%, and 68.2%, respectively. There were no significant differences among survival rates and local control rates between the 3D-CRT and intensity-modulated radiotherapy (IMRT) groups. The main reactions to acute radiotherapy were acute radiation tracheitis, esophagitis, and pneumonia. The tumor location and TNM stage were independent prognostic factors for overall survival. CONCLUSION: The results showed that whole-course CRT and LCAFRT for ESCC can improve survival and local control with a tolerable acute reaction compared to previous studies. Local recurrence and distant metastasis are the main failure modes of treatment. ADVANCES IN KNOWLEDGE: Whole-course CRT and LCAFRT for ESCC can improve the survival and local control rate compared with previous studies from the 2DRT era. It might provide another treatment for patients with inoperable ESCC or refusing surgery.

Improved Pb(II) removal in aqueous solution by sulfide@biochar and polysaccharose-FeS@ biochar composites: Efficiencies and mechanisms.

Novel biochars, namely nano iron sulfide@ walnut shell biochar (FeS@WNS), Starch-FeS@WNS and Chitosan-FeS@WNS, were prepared by WNS loaded with nano FeS and starch (or chitosan). Nano FeS can be effectively improved lead ions (Pb(II)) removal and starch (or chitosan) improved the stability of FeS and the defect of easy agglomeration. The materials were characterized by SEM, EDS, FTIR and XRD, and the preparation was successful. The adsorption capacity of Pb(II) reached 63.5, 80.0, 84.7 mg g-1 under 0.5 g L-1 of FeS@WNS, Starch-FeS@WNS and Chitosan-FeS@WNS. The adsorption of Pb(II) on the materials was more consistent with the pseudo-second-order kinetic model (K2 = 0.001-0.005 g (mg·min)-1, R2 = 0.980-0.999) and Langmuir model (R2 = 0.974-1.00), indicating that the adsorption of Pb(II) was mainly monolayer adsorption dominated by chemical adsorption. △G < 0 (-3.7~-6.97) and △H > 0 (1.56-20.49) indicated that the reaction was a spontaneous endothermic process. The mechanisms of Pb(II) removal from aqueous solutions involved electrostatic attraction, hydrogen bonding, physical adsorption, ion exchange and oxidoreduction. Additionally, stability and reusability of FeS@WNS, Starch-FeS@WNS and Chitosan-FeS@WNS was good. The novel sorbents of Starch-FeS@WNS and Chitosan-FeS@WNS can be used in Pb(II) wastewater treatment.

Synthesis and application of starch-stablized Fe-Mn/biochar composites for the removal of lead from water and soil.

Starch-stablized and Fe/Mn bimetals modified biochar derived from corn straw (SFM@CBC and SFM@CBC-350) were firstly prepared, characterized (FTIR, XRD, SEM, EDS, BET and XPS), and applied in Pb removal from water and soil. SFM@CBC and SFM@CBC-350 displayed highly effective adsorption performance of Pb2+ from wastewater with the maximum adsorption capacity of 170.91 mg g-1 and 190.17 mg g-1, respectively, which were much greater than that of FM@CBC (149.25 mg g-1) and CBC (101.10 mg g-1). Studies of adsorption kinetics, isotherms and thermodynamics indicated that the absorption of Pb2+ by SFM@CBC and SFM@CBC-350 was spontaneous and endothermic reaction, and it was controlled by monolayer chemisorption. The mechanism studies indicated that Pb2+ removal involved with multiple mechanism, including complexation (dominant process confirmed by XPS analysis), physical adsorption, electrostatic attraction, and cation exchange. The reusability test demonstrated that SFM@CBC and SFM@CBC-350 had very good stability and reusability. In addition, in order to further explore Pb removal performance of the modified biochar, SFM@CBC-350 was used in soil-ryegrass pot systems. Compared with the controls, the addition of SFM@CBC-350 reduced Pb content in soil and ryegrass, increased the biomass and total chlorophyll content, reduced the activity of antioxidant enzymes (CAT, SOD, MDA and POD) and ROS fluorescence intensity of ryegrass, thus alleviating Pb stress of ryegrass. Besides, the addition of SFM@CBC-350 could increase the richness and diversity of soil microorganisms, which was beneficial to the growth of ryegrass. Hence, SFM@CBC-350 has the potential of being used as a green, efficient and promising adsorbent in Pb removal from wastewater and soil.

Biochar-supported starch/chitosan-stabilized nano-iron sulfide composites for the removal of lead ions and nitrogen from aqueous solutions.

Novel materials that nano-FeS and starch (or chitosan) loaded on peanut shells biochar(Starch-FeS@PSB and Chitosan-FeS@PSB) were prepared and applied for removal of Pb(II) and nitrogen(NO3-N and NH4-N) in wastewater. It showed that Starch-FeS@PSB and Chitosan-FeS@PSB had excellent absorptive effects compared with PSB. The maximum adsorption capacity of Pb(II) by Starch-FeS@PSB and Chitosan-FeS@PSB reached 91.74 mg/g, 98.04 mg/g, respectively. Absorption of Pb(II) by Starch-FeS@PSB and Chitosan-FeS@PSB were controlled by monolayer chemisorption. Mechanism studies showed that complexation, electrostatic attraction, REDOX and physical absorption happened on the adsorbent surface. In addition, the maximum adsorption capacity of NO3-N and NH4-N by Starch-FeS@PSB and Chitosan-FeS@PSB reached 16.89 mg/g, 15.65 mg/g, and 18.45 mg/g, 18.28 mg/g, respectively. Absorption of N by Starch-FeS@PSB and Chitosan-FeS@PSB were controlled by multilayer chemisorption. Mechanism studies showed that complexation, electrostatic attraction and physical absorption happened on the adsorbent surface. Starch-FeS@PSB and Chitosan-FeS@PSB can be utilized in Pb(II) and N wastewater treatment.

Optimizing the Synthetic Conditions of "Green" Colloidal AgBiS2 Nanocrystals Using a Low-Cost Sulfur Source.

Colloidal AgBiS2 nanocrystals (NCs) have attracted increasing attention as a near-infrared absorbent materials with non-toxic elements and a high absorption coefficient. In recent years, colloidal AgBiS2 NCs have typically been synthesized via the hot injection method using hexamethyldisilathiane (TMS) as the sulfur source. However, the cost of TMS is one of the biggest obstacles to large-scale synthesis of colloidal AgBiS2 NCs. Herein, we synthesized colloidal AgBiS2 NCs using oleylamine@sulfur (OLA-S) solution as the sulfur source instead of TMS and optimized the synthesis conditions of colloidal AgBiS2 NCs. By controlling the reaction injection temperature and the dosage of OLA-S, colloidal AgBiS2 NCs with adjustable size can be synthesized. Compared with TMS-based colloidal AgBiS2 NCs, the colloidal AgBiS2 NCs based on OLA-S has good crystallinity and fewer defects.

In-Depth Insight into the Effect of Hydrophilic-Hydrophobic Group Designing in Amidinium Salts for Perovskite Precursor Solution on Their Photovoltaic Performance.

Amidinium salts have been utilized in perovskite precursor solutions as additives to improve the quality of perovskite films. The design of hydrophilic or hydrophobic groups in amidinium salts is of great importance to photovoltaic device performance and stability in particular. Here we report a contrast study of a guanidinium iodide (GUI) additive with a hydrophilic NH2 group, and a N,1-diiodoformamidine (DIFA) additive with a hydrophobic C-I group, to investigate the group effect. The addition of GUI or DIFA was beneficial to achieve high quality perovskite film and superior photovoltaic device performance. Compared with GUI, the addition of the DIFA in a perovskite precursor solution enhanced the crystal quality, reduced the defect density, and protected the water penetration into perovskite film. The perovskite solar cell (PSC) devices showed the best power conversion efficiency (PCE) of 21.19% for those modified with DIFA, as compared to 18.85% for the control, and 20.85% for those modified with GUI. In benefit to the hydrophobic C-I group, the DIFA-modified perovskite films and PSC exhibited the best light stability, thermal stability, and humidity stability in comparison to the control films and GUI-modified films. Overall, the introduction of a hydrophobic group in the amidinium salts additive was demonstrated to be an efficient approach to achieve high quality and stable perovskite film and PSC devices.

Passivating Quantum Dot Carrier Transport Layer with Metal Salts.

Quantum dots (QDs) have a wide range of applications in the field of optoelectronics. They have been playing multiple roles within the configuration of a device, by serving as the building blocks for both the active layer and the carrier transport layer. While the performance of various optoelectronic devices has been steadily improving via developments in passivating the QD active layer, the possible improvement via passivation of the QD-based carrier transport layer has been largely overlooked. Here, with lead sulfide QD photovoltaics as the platform of study, we demonstrate that the device performance can be significantly improved by passivating the QD hole transport layer (HTL) with zinc salt post-treatments. The power conversion efficiency is improved from 8.7% of the reference device to 10.2% and 9.5% for devices with zinc acetate (ZnAc)- and zinc iodide (ZnI2)-treated HTLs, respectively. Transient absorption spectroscopy confirms that both treatments effectively reduce band-tail states and increase carrier lifetime of the HTLs. Further elemental analysis shows that ZnAc provides a higher amount of Zn2+ for passivation while maintaining the function of HTL by allowing essential p-doping oxidation. In contrast, the additional I- passivation from ZnI2 inhibits p-doping oxidation and limits the function of HTL. This work demonstrates the potential of improving device performance by passivating the QD-based HTLs, and the method developed is likely applicable to other optoelectronic devices.