Despite the outstanding power conversion efficiency of triple-cation perovskite solar cells (PSCs), their low long-term stability in the air is still a major bottleneck for practical applications. The hygroscopic dopants traditionally used in hole transport materials (HTMs) severely degrade the perovskite film. The p-type F4-TCNQ doping of the well-known spiro-OMeTAD HTM enables hydrophobicity-ind

It is universally acknowledged that highly photosensitive transistors are strongly dependent on the high carrier mobility of polymer-based semiconductors. However, the polymer π–π stacking and aggregation, required to increase the charge mobility, conversely inhibit the dissociation of photogenerated charge carriers, in turn accelerating the geminate recombination of electron-hole pairs. To explor

Lead-based halide perovskite nanocrystals (NCs) are recognized as emerging emissive materials with superior photoluminescence (PL) properties. However, the toxicity of lead and the swift chemical decomposition under atmospheric moisture severely hinder their commercialization process. Herein, we report the first colloidal synthesis of lead-free Cs4CuIn2Cl12 layered double perovskite NCs via a faci

In this work, we introduce P3HT (poly(3-hexylthiophene-2,5-diyl)) as an efficient hole transport material (HTM) for lead-free Cs3Sb2I9perovskite-inspired solar cells. The P3HT doubles the power conversion efficiency (PCE) of the solar cells (PCE = 2.5% for the champion device) by improving all of the figures of merit: the fill factor, open-circuit voltage, and the short-circuit current. The maximu

Semiconductor quantum dot (QD) sensitization is one of the most attractive structures to employ QDs for photovoltaic application. The function of QD sensitized solar cells (QDSSC) is controlled by the interfacial charge transfer dynamics. Here we employ transient absorption spectroscopy (TAS) to assess charge transfer dynamics at CdS QD/TiO2 interface, and correlate their dynamics with their solar

We performed a comprehensive study of the charge carrier diffusion in the CsMAFA perovskite, one of the state-of-the-art perovskites for photovoltaic applications, starting from the diffusion of hot carriers to the eventual trapping at the surfaces and grain boundaries. We discovered evidence of non-ambipolar diffusion by using ultrafast transient reflectance spectroscopy: by comparing the transie

The integration of a functional group into dopant-free hole-transport materials (HTMs) to modify the perovskite|HTM interface has become a promising strategy for high-performance and stable perovskite solar cells (PSCs). In this work, a sulfonated phenothiazine-based HTM is reported, namely TAS, which consists of a butterfly structure with a readily synthesized N,​N-​bis[4-​(methylthio)​phenyl]​an

Cesium lead iodide (CsPbI3) perovskite nanocrystals (NCs) suffer from a known transformation at room temperature from their red-emitting (black) to non-emitting (yellow) phase, induced by the tilting of PbI6 octahedra. While the reported attempts to stabilize CsPbI3 NCs mainly involve Pb2+-site doping as well as compositional and/or NC surface engineering, the black phase stability in relation onl

Interfaces play a crucial role in determining perovskite solar cells, (PSCs) performance and stability. It is therefore of great importance to constantly work toward improving their design. This study shows the advantages of using a hole-transport material (HTM) that can anchor to the perovskite surface through halogen bonding (XB). A halo-functional HTM (PFI) is compared to a reference HTM (PF),

The ongoing Internet of Things revolution has led to strong demand for low-cost, ubiquitous light sensing based on easy-to-fabricate, self-powered photodetectors. While solution-processable lead-halide perovskites have raised significant hopes in this regard, toxicity concerns have prompted the search for safer, lead-free perovskite-inspired materials (PIMs) with similar optoelectronic potential.

Double perovskites are a promising family of lead-free materials that not only replace lead but also enable new optoelectronic applications beyond photovoltaics. Recently, a titanium (Ti)-based vacancy-ordered double perovskite, Cs2 TiBr6, has been reported as an example of truly sustainable and earth-abundant perovskite with controversial results in terms of photoluminescence and environmental st

Quantitative assessments of electron and hole transfer dynamics with water on anatase nanocrystalline TiO2 films were conducted by employing a series of transient absorption spectrometers. For water reduction reactions, both conduction band and trapped electrons decay with two different single exponential components with the difference in time scale of 6∼7 orders of magnitudes. The faster reaction

The doping of halide perovskite nanocrystals (NCs) with manganese cations (Mn2+) has recently enabled enhanced stability, novel optical properties, and modulated charge carrier dynamics of the NCs host. However, the influence of Mn doping on the synthetic routes and the band structures of the host has not yet been elucidated. Herein, it is demonstrated that Mn doping promotes a facile, safe, and l

The ability to control the energy levels in semiconductors is compelling for optoelectronic applications. In this study, we managed to tune the work function (WF) of halide perovskite semiconductors using self-assembled monolayers of small molecules to induce stable dipoles at the surface. The direction and intensity of the surface dipoles rely on specific molecule-to-surface interactions. Electro

Most of the high-performing halide perovskite solar cells (PSCs) leverage toxic chlorinated solvents (e.g., o-dichlorobenzene or chlorobenzene) for the hole-transporting material (HTM) processing and/or antisolvents in the perovskite film fabrication. To minimize the environmental and health-related hazards, it is highly desirable, yet at the same time demanding, to develop HTMs and perovskite dep

Colloidal lead-free perovskite nanocrystals have recently received extensive attention because of their facile synthesis, the outstanding size-tunable optoelectronic properties, and less or no toxicity in their commercial applications. Tin (Sn) has so far led to the most efficient lead-free solar cells, yet showing highly unstable characteristics in ambient conditions. Here, we propose the synthes

Copper redox mediators have enabled open-circuit voltages (VOC) of over 1.0 V in dye-sensitized solar cells (DSCs) and have helped to establish DSCs as the most promising solar cell technology in low-light conditions. The addition of additives such as 4-tert-butylpyridine (tBP) to these electrolytes has helped in achieving high solar cell performances. However, emerging evidence suggests that tBP

Phosphorescence colors of cyclodextrin-based insulated Pt-acetylide complexes were tuned by the molecular engineering of the chromophores. A series of Pt complexes bearing various acetylide ligands, including heteroaromatics, were prepared via self-inclusion of the linked macrocycles with the complexes. The decline in the inclusion efficiency derived from the heteroaromatics was overcome by the la

The recently introduced perovskite solar cell (PSC) technology is a promising candidate for providing low-cost energy for future demands. However, one major concern with the technology can be traced back to morphological defects in the electron selective layer (ESL), which deteriorates the solar cell performance. Pinholes in the ESL may lead to an increased surface recombination rate for holes, if

An insulated metallopolymer that undergoes phosphorescence-to-fluorescence conversion between complementary colors by an acid-stimulus is proposed as a color-tunable material. A Pt-based phosphorescent metallopolymer, where the conjugated polymeric backbone is insulated by a cyclodextrin, is depolymerized by HCl via acidic cleavage of Pt-acetylide bonds to form a fluorescent monomer. The insulatio