Two‐terminal Perovskite silicon tandem solar cells with a high‐Bandgap Perovskite absorber enabling voltages over 1.8 V

Abstract

Perovskite silicon tandem solar cells are a promising technology to overcome the efficiency limit of silicon solar cells. Although highest tandem efficiencies have been reported for the inverted p‐i‐n structure, high‐efficiency single junction perovskite solar cells are mostly fabricated in the regular n‐i‐p architecture. In this work, regular n‐i‐p perovskite solar cells with a high‐bandgap mixed cation mixed halide absorber suitable for tandem solar cells are investigated by compositional engineering and the open‐circuit voltage is improved to over 1.12 V using a passivating electron contact. The optimized perovskite solar cell is used as a top cell in a monolithic perovskite silicon tandem device with a silicon heterojunction bottom cell allowing for voltages up to 0.725 V. The tandem solar cells with an active area of 0.25 cm2 achieve record open‐circuit voltages of up to 1.85 V and have efficiencies over 20%. Analyzing the perovskite absorber by spatially resolved photoluminescence measurements shows a homogenous and stable emission at ~ 1.7 eV which is an optimal value for tandem applications with silicon. The tandem solar cells are mainly limited due to a low current. A spectrometric characterization reveals that the perovskite solar cell is current limiting which could be improved by a thicker perovskite absorber.

Review of Interface Passivation of Perovskite Layer

“…After 22 d in air, its PCE remained at above 95% of its initial efficiency and it managed to withstand more than 25 h of continuous thermal stress at 85 °C [ 110 ]. Although some materials do not form a chemical reaction with perovskite materials, PCBM and PMMA have been successfully used to passivate defects in perovskites [ 111 , 112 , 114 , 115 ]. Small-sized passivation molecules can be spontaneously distributed in the grain boundary to enhance the passivation effect of the grain boundary defects of hybrid perovskites [ 48 , 58 , 100 , 116 , 117 ].…”

Interpreting Ideality Factors for Planar Perovskite Solar Cells: Ectypal Diode Theory for Steady-State Operation

“…However, the cells currently lack long-term stability [9]. Success in the economic market (most likely via their incorporation into tandem devices with silicon [10,11]) will depend on our understanding of the fundamental physical mechanisms that control the behavior of PSCs.…”

Temperature-Dependent Optical Band Gap in CsPbBr3, MAPbBr3, and FAPbBr3 Single Crystals

“…Adding bromides increases the band gap compared to corresponding pure iodides, and this favors tandem coupling with silicon in combined photovoltaic technologies. 8 , 9 Their relatively wide band gap is likewise exploited for other optoelectronic applications (LEDs and lasers). In addition to hybrid perovskites, recent developments push toward all-inorganic or Cs-containing materials.…”