Perovskite solar cell

A perovskite solar cell (PSC) is a type of solar cell that includes a perovskite-structured compound, most commonly a hybrid organic–inorganic lead or tin halide-based material as the light-harvesting active layer. Perovskite materials, such as methylammonium lead halides the all-inorganic cesium lead halide, are cheap to produce and simple to manufacture. Solar-cell efficiencies of laboratory-scale devices using these materials have increased from 3.8% in 2009 to 27% in 2025 in single-junction architectures, and, in silicon-based tandem cells, to 34.85%, exceeding the maximum efficiency achieved in single-junction silicon solar cells. Perovskite solar cells have therefore been the fastest-advancing solar technology as of 2016. With the potential of achieving even higher efficiencies and very low production costs, perovskite solar cells have become commercially attractive. Core problems and research subjects include their long-term stability, high sensitivity to moisture, and toxicity if lead is used. Managing toxic lead in PSCs is essential, as exposure presents significant health risks, including neurological disorders. Because PSCs are an emerging technology, lead toxicity remains a major hurdle to widespread adoption and commercialization.

Advantages The raw materials used and the possible fabrication methods (such as various printing techniques) are both low-cost. Their high absorption coefficient enables ultrathin films of around 500 nm to absorb the complete visible solar spectrum. These features combined result in the ability to create low-cost, high-efficiency, thin, lightweight and flexible solar modules. Perovskite solar cells have found use in powering prototypes of low-power wireless electronics for ambient-powered Internet of things applications, and may help mitigate climate change. Perovskite cells also possess many optoelectrical properties that benefit their use in solar cells. For example, the exciton binding energy is small. This allows electron holes and electrons to be easily separated upon the absorption of a photon. Moreover, the long diffusion distance of the charge carrier and the high diffusivity – the rate of diffusion – allow the charge carriers to travel long distances within the perovskite solar cell, which improves the chance of it to be absorbed and converted to power. Lastly, perovskite cells are characterized by wide absorption ranges and high absorption coefficients, which further increase the power efficiency of the solar cell by increasing the range of photon energies that are absorbed. Perovskite solar cells (PSCs) are considered strong candidates in the photovoltaic sector due to their low energy payback time (EPBT), low levelized cost of electricity (LCOE), and rapidly increasing power conversion efficiencies (PCEs). In under two decades, PSCs have reached laboratory efficiencies of 27%, a milestone that monocrystalline silicon required more than 50 years to achieve, owing largely to perovskites' defect tolerance, low recombination losses, and long carrier diffusion lengths. Perovskite materials can also be combined with other photovoltaic technologies in tandem architectures, with perovskite–silicon two-terminal devices recently achieving a record PCE of 34.6%, underscoring their potential for next-generation high-efficiency solar cells.

Materials used

The name "perovskite solar cell" refers to the ABX3 crystal structure of the absorber materials, called perovskite structure, where A and B are cations and X is an anion. A cations with radii between 1.60 Å and 2.50 Å have been found to form perovskite structures. The most commonly studied perovskite absorber is methylammonium lead trihalide (CH3NH3PbX3, where X is a halogen ion such as iodide, bromide, or chloride), which has an optical bandgap between ~1.55 and 2.3 eV, depending on halide content. Formamidinium lead trihalide (H2NCHNH2PbX3) has also shown promise, with bandgaps between 1.48 and 2.2 eV. The perovskite composition H₂NCHNH₂PbI₃ and its favorable bandgap were first reported in the seminal work of Stoumpos, Malliakas, and Kanatzidis on semiconducting tin and lead iodide perovskites, and compositional variants of this system now form the basis of the most efficient perovskite solar cells known today. Its minimum bandgap is closer to the optimal for a single-junction cell than methylammonium lead trihalide, so it should be capable of higher efficiencies. The first use of perovskite in a solid-state solar cell was in a dye-sensitized cell using CsSnI3 as a p-type hole transport layer and absorber. In this all solid state architecture, CsSnI₃ replaced the liquid electrolyte and provided both efficient hole conduction and additional solar light absorption extending into the red and near infrared. This work established that a three dimensional halide perovskite could function as an active semiconducting component in a solid-state device at high efficiency, and it laid essential groundwork for the modern generation of halide perovskite solar cells. A common concern is the inclusion of lead as a component of perovskite materials; solar cells composed from tin-based perovskite absorbers such as CH3NH3SnI3 have also been reported, though with lower power-conversion efficiencies.

Shockley–Queisser limit Solar cell efficiency is limited by the Shockley–Queisser limit. This calculated limit sets the maximum theoretical efficiency of a solar cell using a single junction with no other loss aside from radiative recombination in the solar cell. Based on the AM1.5G global solar spectra, the maximum power conversion efficiency is correlated to a respective bandgap, forming a parabolic relationship. This limit is described by the equation

η = t s × u ( x g ) × v ( f , x g , x c ) × m ( v x g / x c ) {\displaystyle \eta =t_{s}\times u(x_{g})\times v(f,x_{g},x_{c})\times m(vx_{g}/x_{c})}

Where

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