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Abstract:

Abstract Photovoltaics (PVs) are a critical technology for curbing growing levels of anthropogenic greenhouse gas emissions, and meeting increases in future demand for low-carbon electricity. In order to fulfil ambitions for net-zero carbon dioxide equivalent (CO2eq) emissions worldwide, the global cumulative capacity of solar PVs must increase by an order of magnitude from 0.9 TWp in 2021 to 8.5 TWp by 2050 according to the International Renewable Energy Agency, which is considered to be a highly conservative estimate. In 2020, the Henry Royce Institute brought together the UK PV community to discuss the critical technological and infrastructure challenges that need to be overcome to address the vast challenges in accelerating PV deployment. Herein, we examine the key developments in the global community, especially the progress made in the field since this earlier roadmap, bringing together experts primarily from the UK across the breadth of the photovoltaics community. The focus is both on the challenges in improving the efficiency, stability and levelized cost of electricity of current technologies for utility-scale PVs, as well as the fundamental questions in novel technologies that can have a significant impact on emerging markets, such as indoor PVs, space PVs, and agrivoltaics. We discuss challenges in advanced metrology and computational tools, as well as the growing synergies between PVs and solar fuels, and offer a perspective on the environmental sustainability of the PV industry. Through this roadmap, we emphasize promising pathways forward in both the short- and long-term, and for communities working on technologies across a range of maturity levels to learn from each other.

Abstract:

The performance and scalability of perovskite solar cells (PSCs) based on 3D formamidinium lead triiodide (FAPbI3) absorber are often hindered by defects at the surface and grain boundaries of the perovskite. To address this, the study demonstrates the use of pyrrolidinium iodide for the in situ formation of an energetically aligned 1D pyrrolidinium lead triiodide (PyPbI3) capping layer over the 3D FAbI3 perovskite. The thermodynamically stable PyPbI3 perovskitoids, formed through cation exchange reactions, effectively reduce surface and grain boundary defects in the FAPbI3 perovskite. In addition to improved phase stability, the resulting 1D/3D perovskite film forms a cascade energy band alignment with the other functional layers in PSCs, enabling a barrier‐free interfacial charge transport. With a maximum power conversion efficiency (PCE) of ≈23.1% and ≈20.7% at active areas of 0.09 and 1.05 cm2, respectively, the 1D/3D PSCs demonstrate excellent performance and scalability. Leveraging this improved scalability, the study has successfully developed a mechanically‐scribed 1D/3D perovskite mini‐module with an unprecedentedly high PCE of ≈20.6% and a total power output of ≈270 mW at an active area of ≈13.0 cm2. The 1D/3D multi‐dimensional perovskite film developed herein holds great promise for producing low‐cost, high‐performance perovskite photovoltaics at both the cell and module levels.

Abstract:

This study explores the potential of copper-doped nickel oxide (Cu:NiO) as a hole transport layer (HTL) in flexible photovoltaic (PV) devices using a combined first-principles and finite element analysis approach. Density functional theory (DFT) calculations reveal that Cu doping introduces additional states in the valence band of NiO, leading to enhanced charge transport. Notably, Cu:NiO exhibits a direct band gap (reduced from 3.04 eV in NiO to 1.65 eV in the stable supercell structure), facilitating the efficient hole transfer from the active layer. Furthermore, the Fermi level shifts towards the valence band in Cu:NiO, promoting hole mobility. This translates to an improved photovoltaic performance, with Cu:NiO-based HTLs achieving ~18% and ~9% power conversion efficiencies (PCEs) in perovskite and poly 3-hexylthiophene: 1-3-methoxycarbonyl propyl-1-phenyl 6,6 C 61 butyric acid methyl ester (P3HT:PCBM) polymer solar cells, respectively. Finally, a finite element analysis demonstrates the potential of these composite HTLs with Poly 3,4-ethylene dioxythiophene)—polystyrene sulfonate (PEDOT:PSS) in flexible electronics design and the optimization of printing processes. Overall, this work highlights Cu:NiO as a promising candidate for high-performance and flexible organic–inorganic photovoltaic cells.

Abstract:

As perovskite photovoltaics stride towards commercialization, reverse bias degradation in shaded cells that must current match illuminated cells is a serious challenge. Previous research has emphasized the role of iodide and silver oxidation, and the role of hole tunnelling from the electron-transport layer into the perovskite to enable the flow of current under reverse bias in causing degradation. Here we show that device architecture engineering has a significant impact on the reverse bias behaviour of perovskite solar cells. By implementing both a ~35-nm-thick conjugated polymer hole transport layer and a more electrochemically stable back electrode, we demonstrate average breakdown voltages exceeding −15 V, comparable to those of silicon cells. Our strategy for increasing the breakdown voltage reduces the number of bypass diodes needed to protect a solar module that is partially shaded, which has been proven to be an effective strategy for silicon solar panels.