Yang and co-workers reported a dual-function, low-cost, high-performance titanium-nitride-based passivating contact for silicon solar cells. By the implementation of electron-conductive titanium nitride contact, which acts simultaneously as a surface passivating layer and metal electrode, a silicon solar cell with an efficiency of 20% is achieved using a simplified fabrication process. This work also expands the pool of available electron transport materials, from metal oxides to metal nitrides, for photovoltaic devices.

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The difficulty of growing perovskite single crystals in configurations suitable for efficient photovoltaic devices has hampered their exploration as solar cell materials, despite their potential to advance perovskite photovoltaic technology beyond polycrystalline films through markedly lower defect densities and desirable optoelectronic properties. While polycrystalline film absorbers can be deposited on myriad substrates, perovskite single crystals fit for high-efficiency devices have only been demonstrated on hydrophobic hole-transport layers [HTLs, e.g., poly(triaryl amine) (PTAA)], which has severely restricted the avenues for enhancing device efficiency and stability. Herein, we report the growth of mixed-cation FA0.6MA0.4PbI3 perovskite single crystals on a hydrophilic self-assembled monolayer {SAM, [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid), (MeO-2PACz)} HTL surface. Compared with PTAA, the MeO-2PACz SAM promotes the mechanical adhesion of the perovskite on the substrate, enabling the fabrication of inverted solar cells with substantially enhanced operational stability and power conversion efficiencies of up to 23.1%, setting a new benchmark for single-crystal perovskite solar cells.

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Bifacial solar cells are receiving increased attention in the PV market due to their higher energy yield compared to conventional monofacial modules thanks to additional light conversion through their back surface. This additional rear side energy gain creates a potential for significant reduction of the overall levelized cost of energy (LCOE). Despite this fact, wide deployment of bifacial PV modules is very limited because of the high unpredictability of their power output due to various factors such as ground reflectance, module elevation angle, orientation and tilt angle. Due to this complexity, modelling of bifacial modules and systems is currently not developed at the same level of maturity as monofacial ones, where established commercial tools have been developed for PV system designers. In this regard, a customized 2D device model has been developed to simulate bifacial PV structures based on the numerical solution of the transport equations by the finite element method. The model was used to simulate actual PV performance and energy yield based on measured outdoor environmental parameters including solar radiation spectrum and temperature. Bifacial device output was also compared with a monofacial one based on the industrial standard Al-BSF structure. Simulated results were also compared and validated with outdoor experimental data based on IV measurements of monofacial and bifacial modules installed at various tilt angles at a location near the Western coast of Saudi Arabia.