Optimization of Sb2S3 Nanocrystal Concentrations in P3HT: PCBM Layers to Improve the Performance of Polymer Solar Cells

In this study, polymer solar cells were synthesized by adding Sb2S3 nanocrystals (NCs) to thin blended films with polymer poly(3-hexylthiophene)(P3HT) and [6,6]-phenyl-C61-butyric-acid-methyl-ester (PCBM) as the p-type material prepared via the spin-coating method. The purpose of this study is to investigate the dependence of polymer solar cells’ performance on the concentration of Sb2S3 nanocrystals. The effect of the Sb2S3 nanocrystal concentrations (0.01, 0.02, 0.03, and 0.04 mg/mL) in the polymer’s active layer was determined using different characterization techniques. X-ray diffraction (XRD) displayed doped ratio dependences of P3HT crystallite orientations of P3HT crystallites inside a block polymer film. Introducing Sb2S3 NCs increased the light harvesting and regulated the energy levels, improving the electronic parameters. Considerable photoluminescence quenching was observed due to additional excited electron pathways through the Sb2S3 NCs. A UV–visible absorption spectra measurement showed the relationship between the optoelectronic properties and improved surface morphology, and this enhancement was detected by a red shift in the absorption spectrum. The absorber layer’s doping concentration played a definitive role in improving the device’s performance. Using a 0.04 mg/mL doping concentration, a solar cell device with a glass /ITO/PEDOT:PSS/P3HT-PCBM: Sb2S3:NC/MoO3/Ag structure achieved a maximum power conversion efficiency of 2.72%. These Sb2S3 NCs obtained by solvothermal fabrication blended with a P3HT: PCBM polymer, would pave the way for a more effective design of organic photovoltaic devices

Optimization of the Electrochemical Performance of a Composite Polymer Electrolyte Based on PVA-K2CO3-SiO2 Composite

Composite polymer electrolyte (CPE) based on polyvinyl alcohol (PVA) polymer, potassium carbonate (K2CO3) salt, and silica (SiO2) filler was investigated and optimized in this study for improved ionic conductivity and potential window for use in electrochemical devices. Various quantities of SiO2 in wt.% were incorporated into PVA-K2CO3 complex to prepare the CPEs. To study the effect of SiO2 on PVA-K2CO3 composites, the developed electrolytes were characterized for their chemical structure (FTIR), morphology (FESEM), thermal stabilities (TGA), glass transition temperature (differential scanning calorimetry (DSC)), ionic conductivity using electrochemical impedance spectroscopy (EIS), and potential window using linear sweep voltammetry (LSV). Physicochemical characterization results based on thermal and structural analysis indicated that the addition of SiO2 enhanced the amorphous region of the PVA-K2CO3 composites which enhanced the dissociation of the K2CO3 salt into K+ and CO32− and thus resulting in an increase of the ionic conduction of the electrolyte. An optimum ionic conductivity of 3.25 × 10−4 and 7.86 × 10−3 mScm−1 at ambient temperature and at 373.15 K, respectively, at a potential window of 3.35 V was observed at a composition of 15 wt.% SiO2. From FESEM micrographs, the white granules and aggregate seen on the surface of the samples confirm that SiO2 particles have been successfully dispersed into the PVA-K2CO3 matrix. The observed ionic conductivity increased linearly with increase in temperature confirming the electrolyte as temperature-dependent. Based on the observed performance, it can be concluded that the CPEs based on PVA-K2CO3-SiO2 composites could serve as promising candidate for portable and flexible next generation energy storage devices

Realizing 11.3% efficiency in PffBT4T-2OD fullerene organic solar cells via superior charge extraction at interfaces

The influence of interface engineering on the performance and photovoltaic properties of the PffBT4T-2OD poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3′′′-di(2-octyldodecyl)-2,2′;5′,2″;5″,2′′′-quaterthiophen-5,5′′′-diy)] based polymer solar cells (PSCs) are investigated. Owing to the high crystallinity and processing parameter dependent morphology distribution of the PffBT4T-2OD polymer, the performance of the devices can vary significantly with power conversion efficiency (PCE) of around 10% has been reported via such morphology modification. In this work, we demonstrate the effect of trap state passivation at the electron transport layer (ETL)/Polymer interface on the performance of PffBT4T-2OD based PSCs. Aluminium doped ZnO (AZO) and pristine Zinc Oxide (ZnO) are employed as ETLs, which modified the polymer wettability and blend morphology. The interface engineered devices exhibited high PCE of over 11% with high Jsc of about 22.5 mA/cm2 which is about 19% higher than that of the conventional ZnO based devices. The reason behind such distinct enhancements is investigated using several material and device characterization methods including electrochemical impedance spectroscopy (EIS). The recombination resistance (Rrec) of the AZO based device is found to be 4.5 times higher than that of the ZnO devices. The enhanced photovoltaic parameters of the AZO based device are attributed to the superior charge transport characteristics in the ETL as well as at the ETL/polymer interface, enabling effective charge extraction at the respective electrodes with much lesser recombination. The mechanism and the processes behind such enhancements are also elaborated in detail