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To date, most of the reported conjugated materials are p-type semiconductors, while the advances in n-type or ambipolar conjugated materials greatly fall behind those in p-type counterparts. Well-defined n-type semiconductors should possess suitable electron-deficient groups and relatively low lowest unoccupied molecular orbitals (LUMO) levels that facilitate the electron injection and stabilize t
Although many dopant-free hole transport materials (HTMs) for perovskite solar cells (PSCs) have been investigated in the literature, novel and useful molecular designs for high-performance HTMs are still needed. In this work, a hydrogen-bonding association system (NH···CO) between amide and carbonyl is introduced into the pure HTM layer. Our study demonstrates that the hydrogen-bonding associatio
Currently, a high efficiency single layer metal halide perovskite solar cell employs a TiO2 mesoporous layer as an electron transporting material and spiro-OMeTAD as a hole transporting material. The efficient charge carrier separation and retarded interfacial charge recombination are expected to achieve a high solar to energy conversion efficiency. In this presentation, we will demonstrate how st
Designing a hole-transport material (HTM) that guarantees effective hole transport while self-assembling at the perovskite|HTM interface with the formation of an ordered interlayer, has recently emerged as a promising strategy for high-performance and stable perovskite solar cells (PSCs). Hydrogen bonding (HB) is a versatile multi-functional tool for the design of small molecular HTMs. However, to
Realizing ordered structures at the molecular level is a key approach to increase the charge mobility of organic semiconductors. However, the typical solution-based methods employed for the processing make the achievement of well-organized organic nanostructures difficult with the favored formation of disordered assemblies. To realize well-ordered thin films, one needs to design conjugated materia
Lead-free perovskite-inspired materials (PIMs) are gaining attention in optoelectronics due to their low toxicity and inherent air stability. Their wide bandgaps (≈2 eV) make them ideal for indoor light harvesting. However, the investigation of PIMs for indoor photovoltaics (IPVs) is still in its infancy. Herein, the IPV potential of a quaternary PIM, Cu2AgBiI6 (CABI), is demonstrated upon control
The design and synthesis of three star-shaped nonfullerene (NFA) acceptors, TPA-2T-INCN, TPA-2T-BAB, and TPA-T-INCN, based on a triphenylamine (TPA) core and linked through π-conjugated thiophene (T) spacers to different terminal units (3-oxo-2,3-dihydro-1H-inden-1-ylidene) malononitrile, INCN, and 1,3-dimethylbarbituric acid, BAB), are reported. These materials are blended with the widely used po
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
