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Here to determine the thermal stability of buffered layer organic solar cell (BL-OSC), the effect of post anneal treatment has been studied. To investigate the effect of post annealing, the organic solar cells (OSCs) are annealed at the 120°C for different time duration. It has been observed that the BL-OSC structure exhibits the better thermal stability. Further, as the authors vary the post-annealing time duration from 0 min to 20 min, the power conversion efficiency (PCE) in the case BLOSC drops by ~20%, whereas in conventional OSC, the PCE drops by ~35%. This annealing dependent study shows that, in conventional OSC structure an increase in phase segregation between donor and acceptor molecules reduces exciton dissociation and charge separation, this leads to sharp increase in series resistance and significant reduction in fill factor of the device. Whereas in the case of BL-OSS, there is a minimum reduction in the fill factor, which also determines the superior carrier collection and low recombination on the elevated annealing conditions. Further, the experimental results show that, in comparison with the conventional OSC structure, inserting the pure P3HT interlayer between PEDOT:PSS (hole transport layer) and P3HT:PCBM (photoactive layer) improves the PCE of the device by 34%. [ABSTRACT FROM AUTHOR]

Tin oxide thin films were deposited on alumina substrates at 350°C by spray pyrolysis technique. The films were studied after annealing them in air at different temperatures 550°C, 750°C and 950°C for 30 min. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical absorption spectroscopy technique. The grain size was observed to be increased, ranging from 40 to 56.1 nm, with the increase in annealing temperature. Absorbance spectra were taken to examine the optical properties. The band gap energy was observed to be decreased with the increase in annealing temperature. These films were tested to various gases at different operating temperature ranging from 50°C to 450°C. The Tin Oxide film showed maximum sensitivity to H2S gas. The H2S sensing property of the SnO2 films was investigated with different annealing temperatures of the films and at different concentrations of H2S gas. It was found that the annealing temperature of the film significantly affects the sensitivity of the SnO2 to the H2S gas. The maximum sensitivity was found in case of the film annealed at temperature 950°C at the operating temperature 100°C. The sensitivity was found to be increased by 24% in case of the film annealed at 950°C as compared to the sensitivity of the film annealed at 550°C. The observed response of the film was for gas concentration of 10 ppm for H2S with reasonable sensitivity. The quick response and fast recovery are the main features of this film. The effect of annealing temperature on the structural, microstructural, optical and gas sensing properties of the nanocrystalline tin oxide thin films were studied and discussed. [ABSTRACT FROM AUTHOR]

In this work, SnO thin films were deposited onto alumina substrates at 350°C by spray pyrolysis technique. The films were studied after annealing in air at temperatures 550°C, 750°C and 950°C for 30 min. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical absorption spectroscopy technique. The grain size was observed to increase with the increase in annealing temperature. Absorbance spectra were taken to examine the optical properties and bandgap energy was observed to decrease with the increase in annealing temperature. These films were tested in various gases at different operating temperatures ranging from 50-450°C. The film showed maximum sensitivity to HS gas. The HS sensing properties of the SnO films were investigated with different annealing temperatures and HS gas concentrations. It was found that the annealing temperature significantly affects the sensitivity of the SnO to the HS. The sensitivity was found to be maximum for the film annealed at temperature 950°C at an operating temperature of 100°C. The quick response and fast recovery are the main features of this film. The effect of annealing temperature on the optical, structural, morphological and gas sensing properties of the films were studied and discussed. [ABSTRACT FROM AUTHOR]