Evaluation of Blepharoptosis in Patients With Refractory Blepharospasm by VISA-Video Recordings, Idiosyncratic Expressions, Sensory Tricks, and Ancillary Procedures.

BACKGROUND: How to evaluate blepharoptosis concomitantly presented with refractory and uncontrollable blepharospasm? To date, there is a paucity of publications on the ideal evaluation methods. An innovative method-video recordings, idiosyncratic facial expressions, sensory tricks, and ancillary procedures (VISA)-is developed for preoperative evaluation, and the surgical outcomes are demonstrated. METHODS: A retrospective study using VISA for blepharoptosis evaluation was conducted on 51 patients with refractory blepharospasm. Based on the evaluation, patients underwent blepharoptosis correction simultaneously besides the selective myectomy and myotomy in situ of the eyelid protractors for blepharospasm. Preoperative and postoperative palpebral fissure height, margin reflex distance 1, ptosis severity, and levator function were assessed to identify the effectiveness of VISA. All the procedures were performed by the senior author C.-S.L. RESULTS: There were 42 patients diagnosed with essential blepharospasm and 9 patients with Meige syndrome. Forty-one patients (82/102 eyelids [80.4%]) had concomitant blepharoptosis and blepharospasm. Ptosis severity was mild in 21 eyelids (25.6%), moderate in 12 eyelids (14.6%), and severe in 49 eyelids (59.8%). Preoperative/postoperative (6 months) values of palpebral fissure height, margin reflex distance 1, and levator function were 4.70 ± 2.45 mm/8.35 ± 1.33 mm (P < 0.05), -0.30 ± 3.19 mm/3.73 ± 1.05 mm (P < 0.05), and 13.07 ± 2.56 mm/13.68 ± 2.34 mm (P < 0.05), respectively. Undercorrection and revision rate reported 9.8% and 3.7%, individually. CONCLUSIONS: VISA approach overcomes the difficulty of blepharoptosis assessment in patients with refractory blepharospasm. It provides useful preoperative information required for adequate blepharoptosis correction in blepharospasm surgery and yielded desirable outcomes.

The Identification of Subsequent Events Following Out-of-Hospital Cardiac Arrests with Targeted Temperature Management.

Background: Out-of-hospital cardiac arrest (OHCA) is a critical issue due to poor neurological outcomes and high mortality rate. Severe ischemia and reperfusion injury often occur after cardiopulmonary resuscitation (CPR) and return of spontaneous circulation (ROSC). Targeted temperature management (TTM) has been shown to reduce neurological complications among OHCA survivors. However, it is unclear how "time-to-cool" influences clinical outcomes. In this study, we investigated the optimal timing to reach target temperature after cardiac arrest and ROSC. Methods: A total of 568 adults with OHCA and ROSC were admitted for targeted hypothermia assessment. Several events were predicted, including pneumonia, septic shock, gastrointestinal (GI) bleeding, and death. Results: One hundred and eighteen patients [70 men (59.32%); 48 women (40.68%)] were analyzed for clinical outcomes. The duration of CPR after ROSC was significantly associated with pneumonia, septic shock, GI bleeding, and mortality after TTM (all p < 0.001). The duration of CPR was also positively correlated with poor outcomes on the Elixhauser score (p = 0.001), APACHE II score (p = 0.008), Cerebral Performance Categories (CPC) scale (p < 0.001), and Glasgow Coma Scale (GCS) score (p < 0.001). There was a significant association between the duration of CPR and time-to-cool of TTM after ROSC (Pearson value = 0.447, p = 0.001). Pneumonia, septic shock, GI bleeding, and death were significantly higher in the patients who underwent TTM with a time-to-cool exceeding 360 minutes (all p < 0.001). Conclusions: For cardiac arrest patients, early cooling has clear benefits in reducing clinical sequelae. Clinical outcomes could be improved by improving the time to reach target temperature and feasibility for critically ill patients.

Tight adherent feature on optical coherence tomography predict postoperative visual outcome in epiretinal membrane eyes.

BACKGROUND: To identify the predictive parameter among preoperative measurements that best predicts postoperative visual outcome in the epiretinal membrane (ERM). METHODS: Thirty-three consecutive patients with idiopathic unilateral ERM patients between 2015 and 2018 were enrolled. Nineteen healthy normal eyes were selected as an independent age-matched group. Based on preoperative optical coherence tomography (OCT), we further divided the patients with ERM into two groups: type 1, loosely attached ERM, and type 2, tight adherent ERM. We documented the vision and thickness of various retinal layers: nerve fiber layer, ganglion cell layer, inner plexiform layer (GCL + IPL), inner nuclear layer (INL), outer retinal layer (ORL), and retinal pigment epithelium/Bruch complex layer before and after the surgery. The association between postoperative visual acuity and these variables was analyzed using multiple linear regression analysis. RESULTS: All retinal layers of ERM eyes were thicker than the normal eyes (P < 0.05). Among ERMs, we identified 11 eyes with type 1 adhesions and 22 eyes with type 2 adhesions. The preoperative GCL + IPL layers were significantly thicker in type 2 patients than in type 1 patients (93.67 ± 33.03 um vs 167.71 ± 13.77 um; P = 0.023). Greater GCL + IPL thickness was correlated with a worse postoperative visual acuity and multiple linear regression analysis showed that GCL + IPL thickness was an independent predictor of postoperative visual acuity (VA) (beta value = 0.689; P = 0.012). A greater thickness of GCL + IPL layers of type 2 patients had worse postoperative best-corrected visual acuity (BCVA) (P = 0.028). Ectopic inner foveal layers with disappearance of fovea pit were persistently presented in OCT profiles of both groups. CONCLUSION: Idiopathic ERM demonstrated significantly thicker inner retinal layers (GCL + IPL and INL). However, the ORL thickness was similar between the normal eyes and ERM eyes. The preoperative GCL + IPL layers were significantly thicker in patients with type 2 ERM than that in patients with type 1 ERM. The increase in GCL + IPL thickness was significantly correlated with worse postoperative visual outcomes.

The Function-Preserving Frontalis Orbicularis Oculi Muscle Flap for the Correction of Severe Blepharoptosis With Poor Levator Function.

BACKGROUND: Severe blepharoptosis with poor levator function (LF) has traditionally been managed with exogenous frontalis suspension but complications such as lagophthalmos, infection, and rejection are often reported. OBJECTIVES: The aim of this study was to design a function-preserving frontalis orbicularis oculi muscle (FOOM) flap to correct severe blepharoptosis with poor LF. The long-term surgical outcome of the technique was assessed. METHODS: This retrospective study included only adult patients with severe blepharoptosis and poor LF, all of whom had their surgery performed by the senior surgeon over a 6-year period. Clinical assessment of LF, palpebral fissure height (PFH), marginal reflex distance 1 (MRD1), duration of follow-up, and postoperative complications were recorded. RESULTS: A total of 34 patients and 59 eyelids were recorded during a mean follow-up period of 17.7 months. Postoperative evaluation yielded mean [standard deviation] improvements of PFH gain of 5.62 [1.61] mm (P < 0.001), and MRD1 and PFH increases of 4.03 [0.82] mm (P < 0.001) and 8.94 [0.81] mm (P < 0.001), respectively. All patients demonstrated normalization of orbicularis function: no lagophthalmos was observed at the 8-month postoperative follow-up. Recurrence of ptosis was recorded in 4 eyelids (6.78%). Revisions were performed in 2 eyelids (3.39%). No infection or granuloma was noted. CONCLUSIONS: The function-preserving FOOM flap is a useful vector for frontalis suspension. Not only does it effectively address lagophthalmos as well as other complications, but it provides aesthetically pleasing outcomes in patients with severe blepharoptosis and poor LF.

Rectal perforation following endorectal prostate MRI: an unexpected complication.

BACKGROUND: Prostate cancer is a common cancer among men in developed countries. Prostate magnetic resonance imaging (MRI) has been widely employed for early diagnosis of prostate cancer and recommending a treatment plan. The incidence of rectal perforation during endorectal prostate MRI is rare and has never been reported before. Herein, we present a case of rectal perforation after a prostate MRI examination that was subjected to emergency surgical intervention because of the acute presentation of generalized peritonitis. Patients with systemic comorbidities are reportedly at greater risks of encountering colonoscopic perforation. Endorectal prostate MRI is a safe diagnostic modality, but inadequate lubrication of the endorectal coil or over-insufflation of the balloon during the procedure may also lead to serious complications such as hollow organ perforation. Early surgery will be necessary should peritoneal symptoms persist. CASE PRESENTATION: In 2015, a 56-year-old man came to our ER due to acute abdominal pain after he finished his MRI exam. The exam indicated diffuse tenderness over his abdomen and at the ER, his abdominal CT (computerized tomography) was checked. The images revealed extraluminal air in the perirectal fat and the pneumoperitoneum. In response, exploratory laparotomy, simple closure of rectal perforation, and loop-S colostomy were performed and the patient was discharged 1 month after operation. CONCLUSIONS: Prostate MRI is a secure procedure with few complications. Clinicians must keep in mind the possibility of perforation when using ultrasound probe. Hollow organ perforation can result in serious morbidity or death. As a result, patients need to be informed of the complications of prostate MRI. When performing the procedure, clinicians must be cautioned about the potential problems for patients with high-anesthetic risk.

The Epidemiology and Clinical Features of Blepharoptosis in Taiwanese Population.

BACKGROUND: Blepharoptosis describes a condition of low-lying upper eyelid that may affect individuals of all ages under various etiologies. It may be of congenital or acquired form by the timing of onset or be divided into myogenic, neurogenic, aponeurotic, or mechanical types according to the mechanism. Our goal was to report the characteristics of age-specific blepharoptosis and to analyze the association between levator function (LF) and ptosis severity of each ptosis subtype. MATERIALS AND METHODS: The retrospective, single-center, cross-sectional study consisted of patients diagnosed with blepharoptosis in the plastic surgery practice at a medical center between September 2009 and May 2017. We reported patients' age at presentation, sex, laterality of ptosis, etiology, classification, and evaluation of ptosis including levator function and ptosis severity. RESULTS: During a nine-year span of study, a total of 1975 eyelids of 1164 Taiwanese patients aged between 2 and 88 years were enrolled in the research (mean = 57.73 ± 13.41 years). The female-to-male ratio was 2.72 (95% confidence interval [CI]: p < 0.0001). Acquired blepharoptosis and bilateral blepharoptosis were more frequently observed (55.85%, p < 0.0001 and 69.67%, p < 0.0001, respectively). In age-specific relative incidence of blepharoptosis, myogenic ptosis was the majority in patients younger than 40 years. Early onset of aponeurotic ptosis was observed in young contact lenses wearers. Aponeurotic blepharoptosis was the predominant type of ptosis in the senior population older than 40 years (p < 0.0001). Among the subtypes, mechanical ptosis had the most preserved LF (p < 0.0001). LF and MRD1 had statistically positive correlations in all subtypes of blepharoptosis, in which neurogenic ptosis demonstrated the severest levator dysfunction for each millimeter in MRD1 reduction. CONCLUSIONS: Of the 1164 Taiwanese patients, blepharoptosis had a higher propensity for female gender and the age between the second to fourth decades. Bilateral involvement of blepharoptosis with acquired type was frequently diagnosed. Myogenic ptosis had a preponderance in age younger than 40 years, while aponeurotic ptosis usually affects senile population. Many mild degree myogenic ptosis was simultaneously recognized in young-aged adults seeking aesthetic double eyelid surgery. Early onset of acquired aponeurotic ptosis was also observed in contact lens wearers given the trend of decorative contact lens use. Levator dysfunction was implicated in the pathology of not only myogenic ptosis but aponeurotic, mechanical, and neurogenic ptosis. Moreover, levator function of neurogenic ptosis was most severely impacted in each MRD1 reduction among all subtypes of blepharoptosis. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Floppy Eyelid Syndrome: An Unfamiliar Entity for Plastic Surgeons.

BACKGROUND: Floppy eyelid syndrome (FES) is typically characterized by chronic eye irritation and an increased laxity of the upper eyelid that can be easily everted by applying minimal upward traction. However, it is a clinical entity that is less known to most plastic surgeons. Blepharoptosis is one of the most common features, which links to FES, for which a thorough differential diagnosis has become important in directing proper medical treatment. PURPOSE: This review aims to discuss current understanding about FES in a broader spectrum, encompassing the clinical features and evaluation of FES, the underlying etiologies, systemic associations, and surgical procedures for upper eyelid tightening. METHODS: The literature search was conducted in Endnote interface using the keyword "floppy eyelid" through March 2017. All search abstracts were reviewed without language restriction. Citations of identifiable articles were also examined. RESULTS: Despite the exact definition of FES remains ambiguous, patients with FES often demonstrate unresolvable blepharoptosis, dermatochalasis, eyelash ptosis, entropion, or ectropion of the lower eyelid. The pathological course of FES can be worrisome because it is often associated with both ocular and systemic morbidities, most notably papillary conjunctivitis, keratoconus, and obstructive sleep apnea (OSA). Decades of research into the pathogenesis has lent further recognition linking the eyelid floppiness with a loss of elastic fibers, an increased expression of matrix metalloproteinases, and possible collagen gene mutations. Surgery is usually prompted if conservative measures give limited responses. High surgical success rates with different follow-up time have been reported. CONCLUSIONS: For plastic surgeons, early recognition of FES is important because of its chronic, distressing course and the associated morbidities. We believe that surgical intervention is the most effective treatment of choice. The indication for embarking on surgery is based on the clinical severity of the condition. A variety of blepharoplasty techniques for FES have been proposed, including full-thickness wedge excision of the tarsus, medial and lateral canthal ligament ligation, conchal cartilage graft, lateral tarsal strip with flap, and lateral tarsorrhaphy. Most of the procedures have provided excellent visual and aesthetic outcomes; therefore, early surgical intervention is encouraged if early diagnosis can be made.

Antioxidation and antiglycation of Fagopyrum tataricum ethanol extract.

Fagopyrum tataricum is used for the treatment of type 2 diabetes mellitus in Taiwan. The aim of this study was to evaluate the inhibitory effects of 75 % ethanol extract of buckwheat (EEB) and rutin on carbohydrate-metabolized enzymes, including α-amylase and α-glucosidase, which are related to hyperglycemia. The rutin dosage (40 µg/mL) was equivalent to that of EEB (200 µg/mL). In addition, the antioxidant and antiglycation activities of EEB and rutin were investigated. Results showed that both EEB and rutin exerted free radical (DPPH and ABTS) scavenging activity. They also attenuated protein glycation to lower the generation of advanced glycation end-products (AGEs) through the suppression of fructosamine and α-dicarbonyl compounds. Moreover, EEB and rutin also inhibited α-amylase and α-glucosidase activity. Taken together, these findings suggest that EEB and rutin may reduce oxidative stress, AGEs formation, and carbohydrate-metabolized enzymes hence EEB may use as protection agent in diabetic patients.

Ice plant (Mesembryanthemum crystallinum) improves hyperglycaemia and memory impairments in a Wistar rat model of streptozotocin-induced diabetes.

BACKGROUND: Ice plant (Mesembryanthemum crystallinum) has been used as an anti-diabetic agent in Japan because it contains d-pinitol. The efficacy of ice plant in the regulation of blood glucose is unclear at present. Recently, memory impairment and development of Alzheimer's disease found in diabetic patients are thought to be caused by high blood glucose. The mechanism by which ice plant protects against the impairment of memory and learning abilities caused by high blood glucose remains unclear. The aim of this study was to evaluate the protection of ice plant water extracts (IPE) and D-pinitol against memory impairments in a Wistar rat model of streptozotocin (STZ)-induced diabetes. We hypothesised that IPE and D-pinitol could suppress blood glucose and elevate insulin sensitivity in these rats. RESULTS: For memory evaluation, IPE and D-pinitol also improved the passive avoidance task and the working memory task. In addition, inhibition of acetylcholinesterase activity in hippocampus and cortex was found in this rat model administered IPE or D-pinitol. IPE and D-pinitol also markedly elevated superoxide dismutase activity against oxidative stress and reduced malondialdehyde production in hippocampus and cortex of the rats. CONCLUSION: These findings indicated that IPE and D-pinitol possess beneficial effects for neural protection and memory ability in a rat model of diabetes.

Actinidia callosa peel (kiwi fruit) ethanol extracts protected neural cells apoptosis induced by methylglyoxal through Nrf2 activation.

CONTEXT: Methylglyoxal (MG) is a reactive dicarbonyl compound generated as an intermediate of glycolysis during the physical glycation in the diabetic condition. MG itself has been commonly implicated in the development of diabetic neuropathy. Several active compounds in Actinidia callosa have been found to inhibit glycation and MG-protein reaction. OBJECTIVE: This study investigated the protective effects of A. callosa (kiwi fruits) peel ethanol extracts (ACE) on MG-induced Neuro-2A cell apoptosis. MATERIALS AND METHODS: The Neuro-2A cells pre-treated by ACE (50-200 µg/mL) or allyl-isothiocyanate (AITC) (50 µM) for 6 h, in turn, the cells were treated with MG (250 µM) for 24 h. RESULTS: ACE or AITC treatment markedly inhibited the generation of reactive oxygen species (ROS) and the elevation of caspase-3 and capase-9 levels induced by MG in Neuro-2A cells. ACE and AITC elevated Bcl2 and inhibited Bax expressions in MG-induced Neuro-2A cells. ACE elevated Nrf2 transcriptional activity and nuclear translocation in MG-induced Neuro-2A cells. Nrf2 down-stream molecules including HO-1 and GCL were elevated by ACE or AITC treatment in MG-induced Neuro-2A cells. The protective effects of ACE on MG-induced Neuro-2A apoptosis were attenuated while Nrf2 knockdown. DISCUSSION AND CONCLUSION: We established the first evidence that ACE might contribute to the prevention of the development of diabetic neuropathy by blocking the MG-mediated intracellular glycation system.

Resolving conjunctival prolapse following severe blepharoptosis correction: A simple sutureless direct excision technique and systematic review.

BACKGROUND: Conjunctival prolapse (CP) is an uncommon but challenging condition following maximal levator resection (MLR) and other extensive periorbital procedures. MLR extending beyond the Whitnall's ligament is frequently performed to address severe blepharoptosis with poor levator function (LF). Patients with CP may encounter symptoms such as ocular discomfort, tearing, vision impairment, persistent conjunctival chemosis, lagophthalmos, or exposure keratopathy. Typically, surgical intervention becomes necessary if conservative measures prove to be ineffective; nevertheless, there is no consensus regarding the optimal treatment approach. OBJECTIVES: This study aimed to propose a simple sutureless direct excision method and explore the surgical advancements in CP correction through a systematic review. METHODS: Patients with recurrent CP after MLR who underwent sutureless direct excision of the conjunctiva using loupe magnifiers at a tertiary hospital were included in this study. The clinical evolution and surgical results were recorded. PubMed, MEDLINE, EMBASE, and Web of Science databases were queried following The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. RESULTS: The comprehensive analysis of 1858 articles identified 88 patients from 24 studies, highlighting that blepharoptosis surgery is predominantly associated with CP (36.6%). Surgically treated CP showed a higher resolution rate compared to those managed conservatively (54.8% vs. 45.2%; p = 0.034). No relapse was observed in patients treated with sutureless direct excision of CP in long-term follow-up. CONCLUSION: We proposed a simple sutureless direct excision technique that offers a straightforward and efficient approach in treating CP, which is particularly suitable for cases requiring excision lengths >16 mm during MLR. Furthermore, stitch removal can be obviated after surgery.

Regioselective and stereoselective benzylidene installation and one-pot protection of D-mannose.

Oligosaccharide syntheses are an important source of well-defined sugar constructs particularly needed for the evaluation of structure-activity relationships. The chemical assembly of oligosaccharides requires several building blocks, that is, glycosyl donors and acceptors, which are prepared in multistep processes and in a generally tedious and time-consuming manner. Having developed one-pot procedures meant to minimise the effort in sugar building block preparation, we tackled herein the one-pot preparation of fully protected and 2-, 3-, 4-, and 6-alcohol derivatives of d-mannose, a widely distributed monosaccharide. As a consequence of the hydroxyl group pattern of D-mannose, regioselective and stereoselective benzylidenations were developed and later seamlessly utilised as the first transformation in the one-pot procedure.

Regioselective one-pot protection of carbohydrates.

Carbohydrates are involved in a wide range of biological processes. These structurally diverse compounds are more complex than other biological polymers, and are often present as heterogeneous mixtures in nature. The chemical synthesis of carbohydrates is one way to obtain pure oligosaccharides, but it is hampered by difficulties associated with the regioselective protection of polyhydroxyls and challenges related to the stereoselective assembly of glycosidic linkages. Here we describe a combinatorial, and highly-regioselective, method that can be used to protect individual hydroxy groups of a monosaccharide. This approach can be used to install an orthogonal protecting group pattern in a single reaction vessel (a 'one-pot' reaction), which removes the need to carry out the time-consuming isolation and purification of intermediates. Hundreds of building blocks have been efficiently prepared starting from d-glucose, and the iterative coupling of these building blocks enabled us to assemble beta-1,6-glucans and a library of oligosaccharides based on the influenza-virus-binding trisaccharide.

Extended frontalis orbicularis oculi muscle flap shortening for treating refractory apraxia of eyelid opening associated with blepharospasm.

BACKGROUND: Refractory apraxia of eyelid opening (AEO) is mostly unresponsive to botulinum toxin (BTx) and inevitably leads to functional blindness. To treat this challenging condition, an innovative surgical technique was proposed. METHODS: The extended frontalis orbicularis oculi muscle (FOOM) flap shortening consisting of frontalis suspension, partial myectomy, and myotomy in situ of eyelid protractors was applied to treat refractory AEO associated with blepharospasm. The postoperative outcomes and patient satisfaction were evaluated. RESULTS: Seven patients (mean ages 64.1 ± 3.9 years) of 14 eyelids in total had an average flap shortening distance of 24.4 ± 1.3 mm. During a mean follow-up of 31.6 ± 11.4 months, the average BTx dosage reduced from 58.6 ± 12. 1 units to 30.0 ± 8.2 units, with a mean injection interval decreasing from 2.3 ± 0.5 months to 4.1 ± 0.9 months (p < 0.05). Palpebral fissure height increased from 1.4 ± 0.5 mm to 7.9 ± 0.7 mm, and the disability scale decreased from 78.8% ± 7.2% to 12.6% ± 7.0% (p < 0.05). The postoperative BTx dosage and frequency were significantly reduced. All patients restored voluntary eyelid opening and reported high postoperative satisfaction (average Likert scale 4.6 ± 0.5). CONCLUSION: Extended FOOM flap shortening is an effective treatment to solve refractory AEO associated with blepharospasm.

Treatment algorithm for Kimura's disease: A systematic review and meta-analysis of treatment modalities and prognostic predictors.

BACKGROUND: Kimura's disease is a rare, chronic inflammatory condition that usually manifests as highly recurrent head and neck tumors. OBJECTIVE: Systematic review of recurrence predictors following surgical excision. MATERIALS AND METHODS: The pathologically confirmed cases at the tertiary medical center were reviewed. PubMed, Medline, the Cochrane Library, Web of Science, Airiti Library containing grey literature were searched through August 31st, 2019. RESULTS: A total of 31 articles were included for meta-analysis which revealed that surgical excision resulted in a lower recurrence rate (pooled odds ratio [POR] = 3.15, 95% confidence interval [CI] = 1.12-8.82; p = 0.03) than conservative measures. Surgery was an effective single treatment modality for patients with tumors smaller than 3 cm (POR = 2.89, 95% CI: 1.20-6.95; p = 0.02), symptom duration shorter than 5 years (POR = 3.11, 95% CI, 1.03-9.38; p = 0.04), peripheral blood eosinophilia less than 20% (POR = 4.49, 95% CI: 1.46-13.84; p = 0.009) or serum IgE level less than 10000 IU/ml (POR = 8.30, 95% CI: 1.05-65.34; p = 0.04). CONCLUSIONS: Directing patients with Kimura's disease through the treatment algorithm will reduce the recurrence rate. Combination adjuvant therapy with surgery is recommended for the following conditions -- a tumor greater than or equal to 3 cm in size, symptom duration longer than or equal to 5 years, peripheral blood eosinophilia greater than or equal to 20%, or serum IgE greater than or equal to 10000 IU/ml to achieve the optimal therapeutic outcome. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42020173258 (http://www.crd.york.ac.uk/PROSPERO).

Enhancing Efficiency and Stability of Photovoltaic Cells by Using Perovskite/Zr-MOF Heterojunction Including Bilayer and Hybrid Structures.

In this study, the effectiveness of using a perovskite/Zr-metal-organic frameworks (MOFs) heterojunction in realizing efficient and stable inverted p-i-n perovskite solar cells (PVSCs) is demonstrated. Two types of Zr-MOFs, UiO-66 and MOF-808, are investigated owing to their respectable moisture and chemical stabilities. The MOFs while serving as an interlayer in conjunction with the perovskite film are shown to possess the advantages of UV-filtering capability and enhancing perovskite crystallinity. Consequently, the UiO-66/MOF-808-modified PVSCs yield enhanced power conversion efficiencies (PCEs) of 17.01% and 16.55%, outperforming the control device (15.79%). While further utilizing a perovskite/Zr-MOF hybrid heterojunction to fabricate the devices, the hybrid MOFs are found to possibly distribute over the perovskite grain boundary providing a grain-locking effect to simultaneously passivate the defects and to reinforce the film's robustness against moisture invasion. As a result, the PCEs of the UiO-66/MOF-808-hybrid PVSCs are further enhanced to 18.01% and 17.81%, respectively. Besides, over 70% of the initial PCE is retained after being stored in air (25 °C and relative humidity of 60 ± 5%) for over 2 weeks, in contrast to the quick degradation observed for the control device. This study demonstrates the promising potential of using perovskite/MOF heterojunctions to fabricate efficient and stable PVSCs.

Enhanced Near-Infrared Photoresponse of Inverted Perovskite Solar Cells Through Rational Design of Bulk-Heterojunction Electron-Transporting Layers.

How to extend the photoresponse of perovskite solar cells (PVSCs) to the region of near-infrared (NIR)/infrared light has become an appealing research subject in this field since it can better harness the solar irradiation. Herein, the typical fullerene electron-transporting layer (ETL) of an inverted PVSC is systematically engineered to enhance device's NIR photoresponse. A low bandgap nonfullerene acceptor (NFA) is incorporated into the fullerene ETL aiming to intercept the NIR light passing through the device. However, despite forming type II charge transfer with fullerene, the blended NFA cannot enhance the device's NIR photoresponse, as limited by the poor dissociation of photoexciton induced by NIR light. Fortunately, it can be addressed by adding a p-type polymer. The ternary bulk-heterojunction (BHJ) ETL is demonstrated to effectively enhance the device's NIR photoresponse due to the better cascade-energy-level alignment and increased hole mobility. By further optimizing the morphology of such a BHJ ETL, the derived PVSC is finally demonstrated to possess a 40% external quantum efficiency at 800 nm with photoresponse extended to the NIR region (to 950 nm), contributing ≈9% of the overall photocurrent. This study unveils an effective and simple approach for enhancing the NIR photoresponse of inverted PVSCs.