Abstract
Within a short time span of a little over a decade, single junction metal halide perovskites have emerged as perhaps the semiconductor type that has shown the fastest growth in the history of photovoltaic technologies. In addition to its potential applications for single junction architectures, the bandgap tunability of perovskites through compositional engineering to realise both wide and narrow bandgap absorbers have made perovskites an attractive candidate for the development of tandem architectures. Indeed, this led multijunction cell concepts exceed the theoretical limits for single junction silicon photovoltaics while rapidly approaching the limits for other high efficiency single junction absorbers. Within this chapter, we outline the developments made in perovskite/silicon, perovskite/copper–indium–gallium–selenide (CIGS), perovskite/perovskite and emerging triple junction concepts that are based either on a combination of three perovskite absorbers or perovskite/perovskite/silicon type configuration. Particular attention is paid towards modification of interfacial properties for optimising charge extraction and light coupling, the bulk properties for stabilisation of the different perovskite bandgaps and processing strategies that address the challenges that arise during the deposition of perovskites on textured bottom cells such as silicon and CIGS. Finally future directions for research are proposed. This includes the consideration of factors that can accelerate the degradation of perovskites when processing under less well controlled environments as well as considerations for upscaling.