Photoelectric balance of rear electrode in bifacial perovskite solar cells: Construction of 0D/1D/2D composite electrode based on silver nanowires to boost photovoltaic output

Photoelectric imbalance problems of rear transparent conductive electrodes (TCEs) limit the photovoltaic (PV) performance of bifacial planar heterojunction perovskite solar cells (PH-PSCs). We exploit the superior electrical advantages of 0-dimensional (OD) carbon quantum dots (C QDs), 1-dimensional (1D) silver nanowires (Ag NWs), and 2-dimensional (2D) ultrathin Ag films to develop a novel rear TCE with ideal photoelectric balance, i.e., Ag NW + C QD/Ag NW/molybdenum oxide (MoOx)/ultrathin Ag (denoted as A + C/A/M/A) rear TCE with a 0D/1D/2D composite structure. We show that C QDs fully fill the voids within the Ag NW network, which effectively accelerates the charge transfer/collection, thereby enhancing the PV output of PH-PSCs. Moreover, the film quality and photoelectric properties of the rear TCEs are further improved by depositing the MoOx/ultrathin Ag films onto the A + C composite network, which significantly improves PV performance. More importantly, MoOx is key to realizing the photoelectric balance of rear TCEs because it not only has excellent antireflection effects, but also promotes the formation of high-quality ultrathin Ag film. As a result, the efficiencies of the A + C/A/M/A-based PH-PSC under front and rear illuminations are 16.09% and 12.59%, respectively, which are superior to that of most reported Ag NW-based PSCs.