Taiho Park

We developed a novel interface engineering strategy for highly stable and efficient SnO₂-based planar-perovskite solar cells.

Poly[2,5-bis(2-decyldodecyl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione-(E)-1,2-di(2,2′-bithiophen-5-yl) ethene] (PDPPDBTE) was successfully incorporated as a p-type hole transporting material in solid-state organic–inorganic hybrid solar cells. The excellent optical and electrical properties of organo-lead halide perovskite (CH3NH3PbI3) nanocrystals used as light harvesters yielded a 9.2% power conversion efficiency (PCE) for the best-performing cell that exceeded the value (7.6%) obtained from the

A dopant–free polymeric hole transport material (HTM), <bold>RCP</bold>, based on benzo[1,2-<italic>b</italic>:4,5:<italic>b</italic>′]dithiophene and 2,1,3-benzothiadiazole exhibited a high efficiency of 17.3% in a perovskite solar cell and maintained its initial efficiency for over 1400 hours.

Abstract With the application of organic–inorganic hybrid perovskites to liquid‐type solar cells, the unprecedented development of perovskite solar cells (Per‐SCs) has been boosted by the introduction of solid‐state hole transport materials (HTMs). The removal of liquid electrolyte has lead to improved efficiency and stability. Supported by high‐quality perovskite films, the certified efficiency of Per‐SCs has reached 25.2%. For Per‐SCs assembled in a conventional structure (n–i–p), the hole tra

A supramolecular network polymer consisting of a pair of immiscible polymers, poly(butyl)methacrylate (PBMA) and polystyrene (PS), is described. A urea of guanosine (1, UG) and 2,7-diamido-1,8-naphthyridine (2, DAN), which form an exceptionally strong quadruply hydrogen-bonding complex, are displayed at 1-10 mol % along the main backbone of PBMA and PS, respectively. (1)H NMR studies show heterocomplexation between UG and DAN exclusively. This high-fidelity, high-affinity supramolecular connecti

The butyl urea of guanosine (UG) presents an ADDA hydrogen-bonding array that is complementary to the DAAD array of 2,7-diamido-1,8-naphthyridine (DAN). The stability of the DAN.UG complex was measured by fluorimetry using the fluorescence resonance energy transfer (FRET) from the naphthyridine ring to a coumarin 343 moiety linked covalently to the UG unit. The quadruply hydrogen-bonded complex is extremely stable with a measured association constant, Kassoc, of 3 x 108 M-1. Unlike related hydro

Abstract With the recent developments in the efficiency of perovskite solar cells (PSCs), diverse functionalities are necessary for next‐generation charge‐transport layers. Specifically, the hole‐transport layer (HTL) in the various synthesized materials modified with functional groups is explored. A novel donor–acceptor type polymer, alkoxy‐PTEG, composed of benzo[1,2‐b:4,5: b ′]dithiophene and tetraethylene glycol (TEG)‐substituted 2,1,3‐benzothiadiazole is reported. The alkoxy‐PTEG exhibits h

For emerging biocompatible, wearable, and stretchable epidermal electronic devices, it is essential to realize novel stretchable conductors with the attributes of transparency, low-cost and nontoxic components, green-solvent processbility, self-healing, and thermal stabililty. Although conducting materials-rubber composites, ionic hydrogels, organogels have been developed, no stretchable material system that meets all the outlined requirements has been reported. Here, a series of P(SPMA-r-MMA) p

Alternating, multi-block supramolecular copolymers were created using quadruple hydrogen bonding as the noncovalent binding force. One block consisted of two guanosine butyl urea (UG) units attached at the ends of a triethylene glycol linker or a PEG chain (MW = 2 kD). The other block contained a 2,7-diamido-1,8-naphthyridine (DAN) unit at each end of a short alkane diester linker or a 100 kD poly(butyl methacrylate) macromolecule. The UG unit presents an ADDA hydrogen bonding array that is comp

Abstract Organic–inorganic hybrid perovskite has led to the development of new solar cells with outstanding efficiency. In perovskite solar cells (PSCs), perovskite is sandwiched between a working electrode (fluorine‐doped tin oxide) and a counter electrode (gold, Au). In order to transport charges and block opposite charges, charge transport layers are inserted between perovskite and the electrodes. In particular, a hole transport layer is important because it generally prevents perovskite from

Abstract A new naphthalene diimide (NDI)‐based polymer with strong electron withdrawing dicyanothiophene (P(NDI2DT‐TTCN)) is developed as the electron transport layer (ETL) in place of the fullerene‐based ETL in inverted perovskite solar cells (Pero‐SCs). A combination of characterization techniques, including atomic force microscopy, scanning electron microscopy, grazing‐incidence wide‐angle X‐ray scattering, near‐edge X‐ray absorption fine‐structure spectroscopy, space‐charge‐limited current,

Abstract Compact TiO 2 is widely used as an electron transport material in planar‐perovskite solar cells. However, TiO 2 ‐based planar‐perovskite solar cells exhibit low efficiencies due to intrinsic problems such as the unsuitable conduction band energy and low electron extraction ability of TiO 2 . Herein, the planar TiO 2 electron transport layer (ETL) of perovskite solar cells is modified with ionic salt CuI via a simple one‐step spin‐coating process. The p‐type nature of the CuI islands on

We systematically studied the effect of the thickness of a spiro-MeOTAD hole transport layer on photovoltaic properties and reproducibility. We find that an interplay exists between the photovoltaic performance and reproducibility.

An exceptionally strong quadruply hydrogen-bonded complex is formed between 2,7-diamido-1,8-naphthyridine 3 (DAN) and the butylurea of guanosine 6 (UG) in chloroform. The UG unit can be prepared in four steps from guanosine on a 10 g scale in excellent yields without chromatographic purification. The association constant (Kassoc approximately 5 x 10(7) M(-1)) for the UG.DAN complex determined by fluorescence energy transfer from the naphthyridine unit of 3 to coumarin 343 covalently linked UG (1

Although intermolecular charge transport is known to occur via pi-pi stacking, the influence of pi-pi stacking on the mechanical properties of polymers has received little attention compared with other dynamic noncovalent interactions. Herein, we demonstrate a method to enhance stretchability via lowering crystallinity and increasing pi-pi stacking of thiophene-based random copolymer chains, which causes pi-pi stacking-induced polymer networks to form within the fully conjugated semiconducting p