TOPIC 2: Perovskites and Other Thin-Films; Tandems; New Concepts

2.1    Perovskite-based Tandem and Multijunction devices

This subtopic focuses on perovskite-based tandem and multijunction solar cells such as perovskite-silicon, all-perovskite or perovskite combined with other materials. Work addressing lifetime, reliability, stability, scalability, yield, and manufacturability challenge is also covered in this subtopic. For multijunction structures not containing perovskite see subtopic 2.3. For research focusing on the transformation of single-junction silicon cells into designs appropriate for use as silicon bottom cells in multijunction devices, please see Subtopic 1.3. Module level studies, such as manufacturing and field performance may be better placed in Topic 3.

This subtopic brings together the increasing research into tandem and multijunction structures employing perovskites. In the first instance this typically envisages structures on silicon, but all other combinations (such as all-thin-film multijunctions involving perovskite) are welcome. The subtopic comprises theoretical studies, innovations in processing and manufacturing technologies and upscaling, measurement and characterisation. Work related to degradation mechanisms and transient behaviour of the cell materials singly and combined, including improving material composition, and the related stress tests, on packaged cells, mini-modules and packaged mini-modules are to be submitted here, as well as works covering large-area processing and yield uniformity; reproducibility under pilot-line conditions; failure mechanisms in 2T vs 4T tandems at scale; thermo-mechanical stress and industrial module integration. N.B. For III-V multijunction devices and other tandems not employing perovskites, see subtopic 2.3.

2.2    Perovskites

Lead halide perovskites and their lead-less or lead-free analogues, perovskite-based devices, modelling, chemical synthesis, encapsulation, up-scaling technologies and strategies. Work related to improving the lifetime and reliability of perovskite devices. Applied AI techniques. Module level work, such as module manufacturing, characterisation and field performance may be better placed in Topic 3.

The subtopic comprises theoretical studies, innovations in processing and upscaling (including interconnection techniques such as monolithic interconnection via laser scribing), measurement, modelling and characterisation, and reproducibility at multisite and/or multi-laboratory scale. Work related to degradation mechanisms and transient behaviour of the cell materials, including improving material composition, ion migration and its system-level impact, and the related stress tests, on packaged cells, mini-modules and packaged mini-modules are to be submitted here. Multijunctions employing perovskites are excluded from this subtopic (please refer to subtopic 2.1), however, in the case of development of an all-perovskite multijunction, if the focus of the work is on one of the layers only, then it belongs here.

2.3    Compound (Chalcogenide, Kesterite, III-V) and Organic Devices

Compound semiconductors (e.g. II-VI and III-V) and organic devices, materials, surfaces/interfaces and contacts, processing, measurement and characterisation, modelling. Novel cell architectures, materials, technologies and processing for single and multi-junction cells. Work related to improving the lifetime and reliability of such devices. Multijunction devices that do not involve perovskite.

The broad family of chalcogenide and kesterite thin film technologies, e.g. CI(G)S and CZTS, as well as CdTe, are contained in this subtopic; Polymer, organic and dye-sensitized cells and devices are also included. Devices, materials, surfaces/interfaces and contacts, modelling, processing, up-scaling technologies and strategies, quality control, lifetime and reliability measurement and characterisation are all covered. III-V and related compound semiconductors. Multijunction devices that are not covered under subtopic 2.1 (N.B. for research into the transformation of single-junction silicon cells into designs appropriate for use as silicon bottom cells in multijunction devices, please see Subtopic 1.3).

2.4    New Materials, Devices and Conversion Concepts

New cell materials and concepts, e.g., use of nanotechnologies and quantum effects. New module materials and concepts. Application of AI techniques for selection or development of novel materials, cell and module concepts.

Here we invite papers which describe experimental research realising new materials and device concepts, with emphasis on a rather fundamental or prototype (i.e., low Technology Readiness Level, TRL) level.

2.5    New Modelling and Characterization Techniques

Theoretical studies of materials, cells and modules; new measurement techniques, and new modelling and simulation approaches, including applied AI techniques.

This subtopic comprises all theoretical work on photovoltaic conversion as well as, for instance, measurement techniques to reveal e.g., atomic structures or electronic properties.