Technology and the built world

Perovskite mini-module

A perovskite mini-module is a small photovoltaic module in which perovskite solar cells are monolithically series-interconnected on a single substrate, typically 200 to 800 cm².

Perovskite nanocrystal white light-emitting diode

A perovskite nanocrystal white light-emitting diode is a white LED using metal halide perovskite nanocrystals, either down-converting light on blue chips or emitting white directly.

Perovskite optoelectronic synapse

A perovskite optoelectronic synapse is an artificial synaptic device built from metal halide perovskite that mimics biological synaptic plasticity, combining light sensing, memory, and processing for neuromorphic vision systems.

Perovskite oxide electrodes

Perovskite oxide electrodes are ABO₃-type oxide electrodes used as oxygen, air, and fuel electrodes in fuel cells, electrolyzers, and metal-air batteries, valued for low cost and tunable composition.

Perovskite oxygen evolution catalysts

Perovskite oxygen evolution catalysts are tunable ABO₃ oxide compounds that accelerate the oxygen evolution reaction, the efficiency bottleneck of water electrolysis, offering low-cost alternatives to iridium catalysts.

Perovskite passivation

Perovskite passivation is the set of chemical treatments that neutralize defects in metal halide perovskite films, boosting perovskite solar cell efficiency toward 27% and slowing degradation.

Perovskite photodetector

A perovskite photodetector is a light-sensing device using a metal-halide perovskite semiconductor as the photoactive layer, first fabricated in 2014 and matching commercial silicon detectors.

Perovskite photoelectrodes

Perovskite photoelectrodes are semiconductor electrodes, based on ABX3 perovskite materials, that absorb sunlight to drive reactions such as water splitting, CO2 reduction, and nitrogen fixation.

Perovskite quantum dot light-emitting diode

A perovskite quantum dot light-emitting diode, also called PeQLED, is an LED whose emissive layer is metal halide perovskite nanocrystals, developed for high-color-purity displays and lighting.

Perovskite quantum dot solar cells

Perovskite quantum dot solar cells (PQDSCs) are photovoltaic devices whose light-absorbing layer is a film of perovskite nanocrystals, typically FAPbI3, reaching a certified efficiency of 18.23%.

Perovskite quantum-dot LEDs

Perovskite quantum-dot LEDs, or PeQLEDs, are light-emitting diodes that use cesium lead halide perovskite nanocrystals as color-pure, low-cost emitters; their short operating lifetimes hold back commercialization.

Perovskite solar cell

A perovskite solar cell is a photovoltaic device with a lead or tin metal-halide light absorber, whose efficiency has climbed from 3.8% in 2009 to over 26%.

Perovskite solar cell recycling

Perovskite solar cell recycling is the recovery of functional materials, including the lead-halide absorber, from end-of-life perovskite solar cells, since lead toxicity makes it essential for deployment.

Perovskite solar module

A perovskite solar module is a photovoltaic panel whose light-absorbing layer is a metal-halide perovskite thin film, a candidate for low-cost, high-efficiency solar power both alone and in perovskite-silicon tandems.

Perovskite stability under moisture and oxygen

Perovskite stability under moisture and oxygen is how well perovskite solar cells resist water vapor and oxygen, whose reactions decompose the material into lead iodide.

Perovskite tandem solar cell

A perovskite tandem solar cell stacks a wide-bandgap perovskite absorber over silicon or another material, so the two layers capture different parts of the sunlight spectrum and beat either alone.

Perovskite X-ray detector

Halide perovskite X-ray detectors are radiation sensors made of perovskite semiconductors with the crystal formula ABM₃, studied as cheaper, highly sensitive alternatives to silicon and amorphous selenium detectors.

Perovskite-silicon tandem solar cell

A perovskite-silicon tandem solar cell is a photovoltaic device that stacks a perovskite cell on silicon, with certified laboratory efficiency above 35% and first commercial panels shipped in 2024.

Perovskite/CIGS tandem solar cell

A perovskite/CIGS tandem solar cell is a photovoltaic device stacking a wide-bandgap perovskite absorber on a copper indium gallium selenide absorber, lightweight and flexible, with lab efficiencies above 30%.

Perovskite/organic tandem solar cell

A perovskite/organic tandem solar cell is a photovoltaic device stacking a wide-bandgap perovskite sub-cell over a narrow-bandgap organic sub-cell, with lab efficiencies rising from below 17% to over 27%.

Perovskite/quantum-dot tandem solar cells

A perovskite/quantum-dot tandem solar cell is a photovoltaic device that stacks a perovskite top cell over a lead sulfide quantum-dot bottom cell, harvesting both visible and infrared light.

Perpendicular magnetic anisotropy

Perpendicular magnetic anisotropy (PMA) is a magnetic property in which a thin film's easy axis points out of the film plane, underpinning perpendicular recording in hard disk drives and MRAM.

Perpendicular magnetic recording

Perpendicular magnetic recording (PMR) is a hard disk drive technology, proposed by Shunichi Iwasaki in 1975, that stores bits perpendicular to the disk surface for higher density.

Perpendicular magnetic tunnel junction

A perpendicular magnetic tunnel junction (pMTJ) is a magnetic tunnel junction whose two ferromagnetic layers magnetize out of the film plane, enabled by perpendicular magnetic anisotropy.

Perpetual license

A perpetual license is a software license purchased for a one-time fee granting permanent usage rights to a fixed version, in contrast to a subscription that ends when the paid term expires.

Perpetual pavement

Perpetual pavement, also called long-life pavement, is an asphalt pavement designed and built to last more than 50 years, needing only periodic surface renewal, with no structural reconstruction.

Perplexity

Perplexity (PPL) is the standard evaluation metric for language models, measuring how surprised a model is by unseen text; introduced in 1977, it applies to autoregressive models.

Perplexity (AI product)

Perplexity is an AI answer engine that returns cited, multi-paragraph answers synthesized from real-time web results, the flagship product of Perplexity AI, which also offers the Comet browser and Computer agent.

Perplexity AI

Perplexity AI is a San Francisco company founded in 2022 whose answer engine gives direct answers with inline citations instead of link lists, competing with Google and ChatGPT.