Mansoo Choi

It is certain that perovskite materials must be a game-changer in the solar industry as long as their stability reaches a level comparable with the lifetime of a commercialized Si photovoltaic. However, the operational stability of perovskite solar cells and modules still remains unresolved, especially when devices operate in practical energy-harvesting modes represented by maximum power point tracking under 1 sun illumination at ambient conditions. This review article covers from fundamental as

Recently, a mechanical crack-based strain sensor with high sensitivity was proposed by producing free cracks via bending metal coated film with a known curvature. To further enhance sensitivity and controllability, a guided crack formation is needed. Herein, we demonstrate such a ultra-sensitive sensor based on the guided formation of straight mechanical cracks. The sensor has patterned holes on the surface of the device, which concentrate the stress near patterned holes leading to generate unif

A one-step synthesis of onion-like, shell-shaped carbon nanoparticles (SCNPs) is reported. Exposure of an acetylene flow to a continuous-wave infrared CO2 laser produces SCNPs with continuous bent-graphene layers in bulk quantity, but only above a threshold laser power.

Sensors to detect motion with high precision have been extensively studied in diverse engineering research fields.

In mechanical sensory systems, encapsulation is one of the crucial issues to take care of when it comes to protection of the systems from external damage. Recently, a new type of a mechanical strain sensor inspired by spider’s slit organ has been reported, which has incredibly high sensitivity, flexibility, wearability, and multifunctional sensing abilities. In spite of many of these advantages, the sensor is still vulnerable in harsh environments of liquids and/or high temperature, because it h

Abstract As a promising alternative, inorganic perovskite nanocrystals allow reinforced stability of photovoltaic device. Unfortunately, directly assembling these nanocrystals into film is uncontrollable. Instead, in situ assembling technology under low temperature in open air is attractive but limited due to the tendency of nonperovskite transition. The adverse shell ligands and unstable core lattices are known as the fundamental problems. In order to address this issue, here proposed is a rati

Perovskite solar cells (PSCs) have achieved power-conversion efficiency of 25.2%; however, their working principle remains under debate, and the stability issue has not been solved. Herein, we reveal that PSCs are governed by a dominant p–n junction occurring at different interfaces depending on the electron-transporting layer (ETL) and that charge accumulation is mainly concentrated at the corresponding dominant junction where degradation is initiated. To confirm this, we investigated the effec