Comparative architecture in monolithic perovskite/silicon tandem solar cells

Inorganic-organic metal halide perovskite light harvester-based perovskite solar cells (PSCs) with widely tunable bandgap have achieved rapid growth in power conversion efficiency, which exceeds 25% now. It is deliberated that if a semitransparent solar cell made of wider bandgap materials was placed on top of a narrow bandgap materials-based solar cell such as a silicon solar cell, with proper optical and electrical arrangements, the resultant tandem device consisting of two subcells could more effectively utilize the solar spectrum than a single junction solar cell. In a perovskite/silicon tandem solar cell (PSTSC), a semitransparent PSC with a wider bandgap is placed on top of a narrow bandgap silicon solar cell. The PSC efficiently harvests the higher energy photons in the ultraviolet and visible regions of the solar spectrum while the silicon solar cell can convert the photons of the infrared region to power. The PSTSC is proposed as a potential candidate to overcome the Shockley-Queisser limit of single-junction silicon solar cells. Though the theoretical limit of a PSTSC is calculated as ∼42%, its actual efficiency achieved until now is less than 30%. Therefore, a great scope of research exists in improving the efficiency of PSTSCs. Current issues of stability and upscaling of the device in PSCs are also a matter of concern for PSTSCs. A tandem device consists of multiple parts, and different configurations can be applied, thus tuning the architecture of the device. Altering various parts may result in significant changes in the efficiency of the device. In this review, competing architectures of otherwise comparable devices are compared in terms of photovoltaic properties. Thus, future directions to improve the efficiency of the device based on architecture design are proposed herein. In particular, the influence of the polarity of PSCs and the surface morphology of silicon solar cells (both front and rear) on determining the properties of the PSTSC are discussed.