Min Jae Ko

Perovskite solar cells (PSCs) based on organic monovalent cation (methylammonium or formamidinium) have shown excellent optoelectronic properties with high efficiencies above 22%, threatening the status of silicon solar cells. However, critical issues of long‐term stability have to be solved for commercialization. The severe weakness of the state‐of‐the‐art PSCs against moisture originates mainly from the hygroscopic organic cations. Here, rubidium (Rb) is suggested as a promising candidate for

For realizing flexible perovskite solar cells (PSCs), it is important to develop low‐temperature processable interlayer materials with excellent charge transporting properties. Herein, a novel polymeric hole‐transport material based on 1,4‐bis(4‐sulfonatobutoxy)benzene and thiophene moieties (PhNa‐1T) and its application as a hole‐transport layer (HTL) material of high‐performance inverted‐type flexible PSCs are introduced. Compared with the conventionally used poly(3,4‐ethylenedioxythiophene):p

Highly efficient solar cells with sustainable performance under severe mechanical deformations are in great demand for future wearable power supply devices. In this regard, numerous studies have progressed to implement flexible architecture to high‐performance devices such as perovskite solar cells. However, the absence of suitable flexible and stretchable materials has been a great obstacle in the replacement of largely utilized transparent conducting oxides that are limited in flexibility. Her

Abstract Owing to their large surface‐area‐to‐volume ratios, 2D titanium carbides and nitrides (MXenes) have emerged as promising materials for energy storage devices. However, poor interlayer and interparticle conductivity of MXenes (due to its anisotropic nature) is a bottleneck for widening their applications. Additionally, the stacked structure of MXene sheets limits the exposed surface area and renders a complex electrolyte diffusion. To address these issues, a unique composite comprising o

Molecular dynamics is used to characterize the process of crystallization for a united atom model of polyethylene. An oriented melt is produced by uniaxial deformation under constant load, followed by quenching below the melting temperature at zero load. The development of crystallinity is monitored simultaneously using molecular-based order parameters for density, energy, and orientation. For crystallization temperatures ranging from 325 to 375 K, these simulations clearly show the hallmarks of

The efficient electron injection by direct dye-to-TiO(2) charge transfer and strong adhesion of mussel-inspired synthetic polydopamine (PDA) dyes with TiO(2) electrode is demonstrated. Spontaneous self-polymerization of dopamine using dip-coating (DC) and cyclic voltammetry (CV) in basic buffer solution were applied to TiO(2) layers under a nitrogen atmosphere, which offers a facile and reliable synthetic pathway to make the PDA dyes, PDA-DC and PDA-CV, with conformal surface and perform an effi

In this study, we developed a novel nanostructured polymer nanofiber/TiO2 nanoparticle composite photoelectrode with high bendability by a spray-assisted electrospinning method. The composite film is used as the photoelectrode in plastic dye-sensitized solar cells (DSCs). The polymer/TiO2 composite photoelectrode has a structure similar to that of a fiber-reinforced composite; the matrix of the composite photoelectrode contains TiO2 nanoparticles, and PVDF nanofibers are embedded in this matrix.

Recently, scalable perovskite fabrication techniques for large, uniform, and highly crystalline perovskite layers have been developed by controlling the crystal chemistry of perovskite precursors. However, scalable techniques for the electron and hole transport layers (ETL and HTL) have rarely been investigated. A major challenge in a scalable technique is obtaining a uniform, highly crystalline, and ultrathin ETL at a low temperature. Here, large-area SnO2 ETLs are fabricated by an electrostati

We present a new synthetic process of near infrared (NIR)-absorbing copper-indium-selenide (CISe) quantum dots (QDs) and their applications to efficient and completely heavy-metal-free QD-sensitized solar cells (QDSCs). Lewis acid-base reaction of metal iodides and selenocarbamate enabled us to produce chalcopyrite-structured CISe QDs with controlled sizes and compositions. Furthermore, gram-scale production of CISe QDs was achieved with a high reaction yield of ~73%, which is important for the