Organic semiconductor‐based photovoltaic (OPV) devices have many properties that make them attractive for indoor applications, such as tailorable light absorption, low embodied energy manufacturing and cost, structural conformality, and low material toxicity. Compared to their use as organic solar cells (OSCs) for standard outdoor solar harvesting, indoor OPV (IOPV) devices operate at low light intensities, and thus demonstrate different area‐scaling behavior. In particular, it appears as though the performance of large‐area IOPV devices is much less affected by the sheet resistances of the transparent conductive electrodes (a major limit in OSCs), but instead by factors such as their shunt resistance at low light intensities. Herein, the key parameters for improving the efficiency of large‐area IOPV using drift–diffusion and finite element modeling (FEM) are examined. The scaling behavior at low‐light intensities is theoretically and experimentally probed and demonstrated using the model PM6:Y6 system. The implications for the fabrication of large‐area devices and the requirements for high shunt resistances for low‐light performance are examined. These new insights present a clear route toward realizing monolithic large‐area organic photovoltaic cells for indoor applications – which is a necessary technical step to practical implementation.

Organic–inorganic halide perovskite semiconductors have revolutionized next‐generation photovoltaics (PV) due to several characteristics such as solution‐processability, gap tunability, and excellent charge generation and transport properties. This has made them very adaptable for various applications in light harvesting and photodetection. One such rapidly growing application is indoor photovoltaics (IPV) which have the potential to power standalone Internet of Things devices. IPV requires wider optimal bandgaps than solar cells (1.8 vs 1.3 eV) due to the differences between the spectra of artificial lights versus solar radiation. For IPV applications, the active layer wide‐gap perovskite must be developed systemically considering all other components of the device, such as interlayers, electrodes, and scaling. This perspective provides an overview of the potential and challenges facing perovskite‐based IPV from a theoretical, material, and experimental perspective. Furthermore, accurate characterization of perovskite IPVs under simulated indoor conditions is discussed and candidate perovskite PV (PPV) systems are presented to provide insight into IPV development. These include IPV‐optimized formamidinium cesium‐based perovskite, wide‐gap p‐i‐n devices, and 2D perovskite devices, tested under spectrophotometrically calibrated LED illumination at various indoor‐relevant illuminances and benchmarked against thermodynamic predictions. Finally, strategies required to create stable, optimized PPV devices for indoor applications are discussed.

Intense research interest in organic photovoltaic (OPV) devices has resulted in steadily improving figures of merit in recent years. Typically, these devices are fabricated by processing active and buffer layers on transparent conductive electrodes (TCEs). Superlative OPV devices are small (<≈0.1 cm²). The sheet resistance of available monolithic transparent conductive oxide (TCO) materials limits the performance of larger devices and hence the practically attainable cell area. Here, the use of metallic grids in combination with TCOs to create composite TCEs as a means of scaling solution‐processed photovoltaics devices to practical sizes is parameterized. Finite element modeling is used to investigate the relevant design parameters and to estimate figures of merit for realistic organic solar cells. It is shown that the scalability of devices with metallic grids improves significantly when grids are implemented at micrometer scales. Representative silver grids are fabricated and the optical and electrical properties of the resulting structures are measured. Overall, these findings indicate that metallic grids can be designed to develop large‐area solution‐processed solar cells with currently available fabrication techniques.

Graphene-based point-of-care (PoC) and chemical sensors can be fabricated using photolithographic processes at wafer-scale. However, these approaches are known to leave polymer residues on the graphene surface, which are difficult to remove completely. In addition, graphene growth and transfer processes can introduce defects into the graphene layer. Both defects and resist contamination can affect the homogeneity of graphene-based PoC sensors, leading to inconsistent device performance and unreliable sensing. Sensor reliability is also affected by the harsh chemical environments used for chemical functionalisation of graphene PoC sensors, which can degrade parts of the sensor device. Therefore, a reliable, wafer-scale method of passivation, which isolates the graphene from the rest of the device, protecting the less robust device features from any aggressive chemicals, must be devised. This work covers the application of molecular vapour deposition technology to create a dielectric passivation film that protects graphene-based biosensing devices from harsh chemicals. We utilise a previously reported “healing effect” of Al₂O₃ on graphene to reduce photoresist residue from the graphene surface and reduce the prevalence of graphene defects to improve graphene device homogeneity. The improvement in device consistency allows for more reliable, homogeneous graphene devices, that can be fabricated at wafer-scale for sensing and biosensing applications.