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Single junction crystalline silicon (c‐Si) solar cells are reaching their practical efficiency limit whereas perovskite/c‐Si tandem solar cells have achieved efficiencies above the theoretical limit of single junction c‐Si solar cells. Next to low‐thermal budget silicon heterojunction architecture, high‐thermal budget carrier‐selective passivating contacts (CSPCs) based on polycrystalline‐SiOx (poly‐SiOx) also constitute a promising architecture for high efficiency perovskite/c‐Si tandem solar cells. In this work, we present the development of c‐Si bottom cells based on high temperature poly‐SiOx CSPCs and demonstrate novel high efficiency four‐terminal (4T) and two‐terminal (2T) perovskite/c‐Si tandem solar cells. First, we tuned the ultra‐thin, thermally grown SiOx. Then we optimized the passivation properties of p‐type and n‐type doped poly‐SiOx CSPCs. Here, we have optimized the p‐type doped poly‐SiOx CSPC on textured interfaces via a two‐step annealing process. Finally, we integrated such bottom solar cells in both 4T and 2T tandems, achieving 28.1% and 23.2% conversion efficiency, respectively. [ABSTRACT FROM AUTHOR]

Recently perovskite/crystalline Si (cSi) tandem cells draw considerable attention because their high efficiency can reduce the levelized cost of electricity and increase the power density of photovoltaics (PVs) to accelerate the energy transition. While the theoretical limits for tandem cells are well known, the practical limits are less clear. Herein, a new method is presented to calculate the efficiency of a four-terminal (4T) tandem based on the performance of singlejunction perovskite and cSi cells, using their detailed-balance efficiency fraction. This calculation method is validated with experiments on 4T perovskite/cSi tandem cells that provide a maximum efficiency of 28.0% and with the literature data available for similar configurations. A maximum efficiency of about 36% is estimated for 4T perovskite/cSi tandem cells that would use present record perovskite and cSi PV cells. This can be regarded as the practical efficiency limit for 4T perovskite/cSi tandem devices. [ABSTRACT FROM AUTHOR]

Sputtered transparent conducting oxides (TCOs) are widely accepted transparent electrodes for several types of high‐efficiency solar cells. However, the different sputtering yield of atoms makes stoichiometric transfer of target material challenging for multi‐compounds. Additionally, the high kinetic energies of the arriving species may damage sensitive functional layers beneath. Conversely, pulsed laser deposition (PLD) is operated at higher deposition pressures promoting thermalization of particles. This leads to stoichiometric transfer and additionally reduces the kinetic energy of ablated species. Despite these advantages, PLD is rarely used within the photovoltaic community due to concerns about low deposition rates and the scalability of the technique. In this study, wafer‐scale (4‐inch) PLD of high‐mobility Zr‐doped In2O3 (IZrO) TCO for solar cells is demonstrated. IZrO films are grown at room temperature with deposition rate on par with RF‐sputtering (>4 nm min−1). As‐deposited IZrO films are mostly amorphous and exhibit excellent optoelectronic properties after solid phase crystallization at <200 °C. 100‐nm thick films feature a sheet resistance of 21 Ω◻−1 with electron mobilities ≈70 cm2 V−1s−1. PLD‐grown IZrO is applied as rear electrode in efficient semi‐transparent halide perovskite solar cells leading to the improved stabilized maximum power point efficiency (15.1%) as compared to the cells with sputtered ITO electrodes (11.9%). [ABSTRACT FROM AUTHOR]

We report a cooperative study conducted between different laboratories to investigate organic solar cell degradation with respect to P3HT material properties and different solar cell architectures. Various batches of P3HT were collected from different suppliers reflecting commercial availability as well as properties variability. Among the materials properties explicitly considered were the molar mass, dispersity, regio-regularity, impurities by trace metals and intrinsic doping evaluated from radical concentrations. Each of the participating laboratories contributing test devices applied their own layer stack, i.e. their own device architecture and layout. This variation was appreciated as another parameter for evaluation. Even though a large amount of devices failed due to extrinsic degradation effects, indeed, some materials properties were found to be more important than others for obtaining long lifetimes and high stability of P3HT-based polymer solar cells. • P3HT:PCBM solar cells made from commercially available P3HTs were aged under three different ISOS protocols. • Solar cells were built by five different labs resulting in 5 different architectures. • The P3HT batches were studied for their properties like impurities, molar mass, dispersity, etc. • All P3HTs performed similar in regard to stability we concluded that commercially available P3HTs offer viable properties. • Layer stack and processor experience with P3HT used had a larger impact on stability than polymer properties. [ABSTRACT FROM AUTHOR]