Simulation of highly efficient GeSe-based solar cells with SCAPS-1D.

Recently GeSe has developed as a promising light harvesting material by enjoying to its optical and electrical features as well as earth-abundant and low-toxic constituent elements. Nevertheless, the power conversion efficiency of GeSe-based solar cells yet lags far behind the Shockley-Queisser limit. In this work, we systematically designed, simulated and analyzed the highly efficient GeSe thin-film solar cells by SCAPS-1D. The influence of thickness and defect density of light harvest material, GeSe/CdS interface defect density, electron transport layer (ETL), electrode work function and hole transport layer (HTL) on the device output are carefully analyzed. By optimizing the parameters (thickness, defect, concentration, work function, ETL and HTL), an impressive PCE of 17.98% is delivered along with Jsc of 37.11 mA/cm2, FF of 75.53%, Voc of 0.61 V. This work offers theoretical guidance for the design of highly efficient GeSe thin film solar cells.

[Characterization of Sludge Morphology and Bacterial Community Evolution in the Rapid Activation of Freeze-stored PN/A Granular Sludge].

Inoculating granular sludge is an alternative method for the quick start-up of a high-performance autotrophic nitrogen removal reactor. In order to establish the response relationship between sludge activation and reactor performance, the freeze-stored granular sludge was inoculated into a continuous-flow reactor, and a control strategy of the high loading rate and high hydraulic selective pressure was carried out in this study. As a result, a one-stage partial nitritation/ANAMMOX process was started up in 34 days, and the removal efficiency of total nitrogen was over 83%, with a removal loading rate of total nitrogen of 1.67 kg·(m3·d)-1. During this period, the Image pro-plus software was employed to analyze the evolution of the characteristic dimensions of particles. A good linear positive correlation (R2=0.988) between the projected area of the erythrine zone in the inner layer and the specific nitrogen removal rate of granules was found, which provide a simple method to estimate the activity of the PN/A granules. The results of MiSeq high-throughput sequencing showed that the enrichment of aerobic ammonia-oxidizing bacteria (Nitrosomonas) and the wash-out of heterotrophic bacteria (such as Denitratisoma and Haliangium, etc.) were achieved in the start-up of the reactor. Meanwhile, the improvement in granular compactness was in favor of activating anaerobic ammonia oxidizing bacteria (Candidatus_Kuenenia, abundance>30%) that colonized the inner layer of the granules.