Reverse-Bias and Temperature Behaviors of Perovskite Solar Cells at Extended Voltage Range

Abstract

Perovskite solar cells have reached certified power conversion efficiency over 25%, enabling the realization of efficient large-area modules and even solar farms. It is therefore essential to deal with technical aspects, including the reverse-bias operation and hot-spot effects, which are crucial for the practical implementation of any photovoltaic technology. Here, we analyze the reverse bias (from 2.5 to 30 V) and temperature behavior of mesoscopic cells through infrared thermal imaging coupled with current density measurements. We show that the occurrence of local heating (hot-spots) and arc faults, caused by local shunts, must be considered during cell and module designing.

Halogen Redox Shuttle Explains Voltage-Induced Halide Redistribution in Mixed-Halide Perovskite Devices

“…To begin with, we review two practically important perovskite devices that require band-gap tunability and regularly experience large voltages under nonilluminated conditions that can induce halide segregation: (1) partial shading within photovoltaic modules that thrust the affected cells into reverse bias (Figure A) − and (2) normal operation of perovskite light-emitting diodes (LEDs, Figure B). First, if we consider a photovoltaic module where many cells are connected in series, depending on how many cells are in the string and the number of bypass diodes that are used in the module, the reverse bias dropped on the shaded cell can be higher than 10 V (if there is less than one bypass diode per 10 cells). − Then, for perovskite LEDs, the maximum external quantum efficiency typically occurs at the injection current density between 10 0 and 10 3 mA cm –2 , , which requires voltages in the range of 2–5 V. − Thus, bright and efficient operation of perovskite LEDs usually requires a forward bias of above 2 V, and depending on the band gap and morphology of the perovskite emission layer as well as the required brightness, some perovskite LEDs may operate at a forward bias as high as 10 V . The high voltage biases inherent to these two situations can cause strong voltage-induced halide segregation, which (in the absence of light) dominates the phase stability of mixed-halide perovskite devices and negates the band-gap/color tunability.…”

Functionalized Metallic 2D Transition Metal Dichalcogenide-Based Solid-State Electrolyte for Flexible All-Solid-State Supercapacitors

“…The global demand for energy and noticeable depletion of fossil fuels during the past decade has caused energy crises and environmental concerns, − calling for a pathway toward the transformation of the global energy sector from fossil-based to zero-carbon, i.e., the so-called energy transition. , In this context, energy storage technologies represent essential enablers of the energy transition, since they can overcome the issues related to the variable output of renewable energy sources, , resulting in resilient decarbonized electric grids. , Meanwhile, they also play a crucial role in developing decentralized power networks, i.e., the so-called “microgrids”, for small-scale self-sufficient organizations , and even portable and wearable electronics. − …”

Two-dimensional BiTeI as a novel perovskite additive for printable perovskite solar cells

“…The power conversion efficiency (PCE) of perovskite solar cells (PSCs) has been continuously increasing for the last 10 years to more than 25%, 1,2 approaching the record-high values of Si-based solar cells. 3 Despite the promise of PSCs, it is still crucial to solve the remaining challenges related to stability, 4,5 performance reproducibility, and reliability, 6,7 which call for the urgent exploration of novel non-complex and cost-effective manufacturing procedures. 8–10 The optimization of the charge transporting layers at the interfaces with the perovskite is a prototypical route to tune the material energy alignment across the cell structure so that favorable material energy offsets can lead to PCE maximization.…”