Synergetic effects of a front ITO nanocylinder array and a back square Al array to enhance light absorption for organic solar cells.

Efficient light management is critical to obtain high performance for organic solar cells (OSCs), which aims to solve the contradiction between limited carrier extraction and light absorption for the normally employed photoactive layers generally having both short exciton diffusion lengths and low extinction coefficients. In this study, we introduce a simple and efficient light management structure consisting of a front indium tin oxide nanocylinder (ITO-NC) array and a back square Al array. Thanks to the synergetic effects of antireflection and light scattering induced by the ITO-NC array, together with the secondary scattering and localized surface plasmon resonance because of the square Al array, remarkably enhanced light absorption in a broad spectral range can be achieved. Taking the most investigated photoactive layer of the P3HT:PC61BM blend as an example, simulation results reveal that, compared with the planar control device of the ITO/PEDOT:PSS/P3HT:PC61BM(80nm)/ZnO/Al, the short-circuit current density and power conversion efficiency can be enhanced by 36.58% and 38.38% after incorporating the light management structure with the optimal structural parameters. Furthermore, good omnidirectional light management can be achieved for the proposed device structure. Given the excellent performance and simple structure, we believe that this study would provide a meaningful exploration of developing light management structures applicable for thin film-based optoelectronic devices.

Improved Comprehensive Photovoltaic Performance and Mechanisms by Additive Engineering of Ti3C2Tx MXene into CsPbI2Br.

CsPbI2Br is promising in the application of perovskite solar cells (PSCs) owing to its reasonable bandgap and good thermal stability. However, the reported power conversion efficiency (PCE) of the CsPbI2Br solar cells is still much lower than that of the organic-inorganic hybrid PSCs, mainly due to relatively poor CsPbI2Br crystal quality. Herein, additive engineering to the photoactive layer of CsPbI2Br using the Ti3C2Tx MXene nanosheets is reported. Thanks to the improved crystallinity/reduced defect density, together with the formation of the Schottky junction between the MXene nanosheets and CsPbI2Br, enhanced separation and transfer of the photogenerated electron-hole pairs can be achieved for optimal MXene addition. A simple device configuration of ITO/SnO2/Ti3C2Tx-added CsPbI2Br/P3HT/Ag can thus deliver a significantly boosted PCE of 15.10%, i.e., a ∼16.69% relative increment compared with that (12.94%) of the control device without adding MXene. In addition, the enhanced humidity resistance is achieved for the MXene-added CsPbI2Br layers.