Control of defect processes in photovoltaic materials is essential for realizing high-efficiency solar cells and related optoelectronic devices. Native defects and extrinsic dopants tune the Fermi level and enable semiconducting p–n junctions; however, fundamental limits to doping exist in many compounds. Optical transitions from defect states can enhance photocurrent generation through sub-bandgap absorption; however, these defect states are also often responsible for carrier trapping and non-radiative recombination events that limit the voltage in operating solar cells. Many classes of materials, including metal oxides, chalcogenides and halides, are being examined for next-generation solar energy applications, and each technology faces distinct challenges that could benefit from point defect engineering. Here, we review the evolution in the understanding of point defect behaviour from Si-based photovoltaics to thin-film CdTe and Cu(In,Ga)Se₂ technologies, through to the latest generation of halide perovskite (CH₃NH₃PbI₃) and kesterite (Cu₂ZnSnS₄) devices. We focus on the chemical bonding that underpins the defect chemistry and the atomistic processes associated with the photophysics of charge-carrier generation, trapping and recombination in solar cells. Finally, we outline general principles to enable defect control in complex semiconducting materials.

控制光伏材料中的缺陷过程对于实现高效太阳能电池和相关的光电设备至关重要。天然缺陷和非本征掺杂剂可调节费米能级并实现半导体p–n结。但是，许多化合物中都存在掺杂的基本限制。缺陷态的光学跃迁可以通过子带隙吸收增强光电流的产生；然而，这些缺陷状态通常还导致载流子捕获和非辐射复合事件，这些事件限制了正在运行的太阳能电池中的电压。正在针对下一代太阳能应用检查包括金属氧化物，硫属元素化物和卤化物在内的多种材料，每种技术都面临着可以从点缺陷工程中受益的独特挑战。这里，_2项技术中，通过对最新一代的卤化物钙钛矿（CH ₃ NH ₃碘化铅₃）和锌黄锡矿（CU _2个ZnSnS ₄）设备。我们专注于化学键，该化学键是缺陷化学的基础，是与太阳能电池中电荷载流子的产生，俘获和复合的光物理相关的原子过程的基础。最后，我们概述了在复杂的半导体材料中实现缺陷控制的一般原则。