Colloidal quantum dots (QDs) of lead halide perovskite have recently received great attention owing to their remarkable performances in optoelectronic applications. However, their wide applications are hindered from toxic lead element, which is not environment- and consumer-friendly. Herein, we utilized heterovalent substitution of divalent lead (Pb) with trivalent antimony (Sb) to synthesize stable and brightly luminescent CsSbBr QDs. The lead-free, full-inorganic QDs were fabricated by a modified ligand-assisted reprecipitation strategy. A photoluminescence quantum yield (PLQY) was determined to be 46% at 410 nm, which was superior to that of other reported halide perovskite QDs. The PL enhancement mechanism was unraveled by surface composition derived quantum-well band structure and their large exciton binding energy. The Br-rich surface and the observed 530 meV exciton binding energy were proposed to guarantee the efficient radiative recombination. In addition, we can also tune the inorganic perovskite QD (CsSbX) emission wavelength from 370 to 560 nm via anion exchange reactions. The developed full-inorganic lead-free Sb-perovskite QDs with high PLQY and stable emission promise great potential for efficient emission candidates.

Hygroscopicity risk and organic-inorganic hybrid perovskites easy decomposition in solar cells limit their usefulness. Apart from the hybrid organicinorganic perovskites, inorganic perovskite solar cells display a better stability toward moisture, light soaking, and thermal stressing. However, most inorganic perovskites are inappropriate for single junction or tandem solar cells due to their large bandgaps (>1.8 eV), which eventually results in light absorption loss. Fortunately, cubic CsPbI 3 perovskite (having 1.73 eV bandgap) could potentially serve as top cells in tandem devices with silicon solar cells. Poor phase stability of CsPbI 3 is considered a major obstacle to design CsPbI 3 perovskite solar cells. This review highlights the most recent studies on the progress in CsPbI 3 -based solar cell device field. Moreover, this review also summarizes certain strategies to improve phase stability, such as size reduction to nanocrystal or external cations/anions doping, with the aim to improve the devices design.

The transitionmetal dichalcogenides‐based phototransistors have demonstrated high transport mobility but are limited to poor photoresponse, which greatly blocks their applications in optoelectronic fields. Here, light sensitive PbS colloidal quantum dots (QDs) combined with 2D WSe2 to develop hybrid QDs/2D‐WSe2 phototransistors for high performance and broadband photodetection are utilized. The device shows a responsivity up to 2 × 105 A W–1, which is orders of magnitude higher than the counterpart of individual material‐based devices. The detection spectra of hybrid devices can be extended to near infrared similar to QDs' response. The high performance of hybrid 0D‐2D phototransistor is ascribed to the synergistic function of photogating effect. PbS QDs can efficiently absorb the input illumination and 2D WSe2 supports a transport expressway for injected photocarriers. The hybrid phototransistors obtain a specific detectivity over 1013 Jones in both ON and OFF state in contrast to the depleted working state (OFF) for other reported QDs/2D phototransistors. The present device construction strategy, photogating enhanced performance, and robust device working conditions contain high potential for future optoelectronic devices.

sensitivity are the bottlenecks in future commercialization applications. [4,5] Fully-inorganic lead halide perovskites (APbX 3 , A = Cs, Rb, K, etc.), without the organic part affection were expected to resolve the problem of stability. [4,6,7] According to the work of Kubelk et al., fullyinorganic perovskites have similar bandgaps to organo-lead halide analogs and hold much better thermal stability. [4,[7][8][9] Under the scenario of lead-free perovskite, tin (Sn) and germanium (Ge) elements have been considered as hot candidates [10] to replace lead. However, the quick oxidation from Sn 2+ /Ge 2+ to Sn 4+ /Ge 4+ greatly degrades their PCE. [11][12][13] To overcome this problem, heterovalent elements of Sb and Bi were introduced for the implementation of green perovskite. And these perovskite molecular structures transmute from ABX 3 to their derivatives such as A 3 B 2 X 9 .For antimony iodide perovskite (AIP) [14,15] research work, Mitzi and our group combined theoretical calculations, film deposition, and experimental characterizations to understand this new absorber semiconductor. Two kinds of polymorphs exist for Cs 3 Sb 2 I 9 , 0D (dimer) and 2D (layered) phases. Dimer phase exhibits indirect bandgap of 2.50 eV unfavorable for photo voltaics, while layered phase has a direct bandgap of 2.05 eV, a suitable choice as active absorber. The latter one provides similar high level of absorption as CH 3 NH 2 PbI 3 and relatively small in-plane and out-of-plane effective mass. [16][17][18] The layered film could only be synthesized by vapor method with annealing temperature ≈300 °C under the assistance of SbI 3 vapor. [16] Utilizing similar SbI 3 vapor reaction with CsI and SbI 3 precursor film, Chu and co-workers obtained AIP-layered thin film solar cells via a structure of ITO/PEDOT:PSS/AIP/ PC 70 BM/Al and obtained a PCE value of 1.49%. [19] In addition to unique optoelectronic properties, LIP solar cells obtained huge progress highly relying on convenient solution method. The present layered AIP vapor method required high reaction temperature as well as nonuniform composition. Thus, we tried to develop a simple solution method for layered AIP absorbers. According to Zhou and co-workers' theoretical calculations, the AIP dimer phase is an energetically stable Since lead halide perovskite suffers from the obstructions of lead and stability, researchers recently pay more attention to the development of lead-free and stable perovskite absorbers. A typical lead-free antimony iodide perovskite (AIP) is synthesized through vapor reaction at high temperature for photoactive phase. Herein, hydrochloric acid is developed as an intermediate coordinated additive for Cs 3 Sb 2 I 9 photoactive layered phase using HCl-assisted solution method. The uniform and highly crystalline Cs 3 Sb 2 I 9 layered film is obtained by antisolvent engineering. Isopropanol antisolvent is more suitable for present system comparing with traditional lead iodide perovskite-based ones. Physical characterizations manifest the lower trap density, do...

Sb 2 S 3 has attracted great research interest very recently as a promising absorber material for thin film photovoltaics because of their unique optical and electrical properties, binary compound and easy synthesis. Sb 2 S 3 planar solar cells from evaporation method without hole-transport layer (HTM) assistance suffer from sulfur deficit vacancy and high back contact barrier. Herein, we developed a postsurface selenization treatment to Sb 2 S 3 thin film in order to improve the device performance. The XRD, Raman, and UV−vis spectra indicated the treated film kept the typical characters of Sb 2 S 3 . TEM/EELS mapping of treated Sb 2 S 3 film revealed that only surface adjacent section was partly selenized and formed Sb 2 (S x Se 1−x ) 3 alloy. In addition, XPS results further unfolded that there was trace selenium doping in the bulk of Sb 2 S 3 film. The treated HTM-free Sb 2 S 3 based solar cells were fabricated and an improved efficiency of 4.17% was obtained. The obtained V OC of 0.714 V was the highest and the power conversion efficiency also reached the top value among HTM-free planar Sb 2 S 3 solar cells. The nonencapsulated device exhibited high stability. After storing in ambient air for up to 100 days, the device could maintain 90% efficiency. Systematic materials and device characterizations were implemented to investigate the improvement mechanism for postsurface selenization. The back alloying could suppress the rear contact barrier to improve the fill factor and carrier extraction capability. The bulk Se-doping helped to passivate the interface and bulk defects so as to improve the CdS/Sb 2 S 3 heterojunction quality and enhance the long-wavelength photon quantum yield. The robust treatment method with multifunctional effect holds great potential for new chalcogenide thin film solar cell optimization.

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This work incorporates a variety of conjugated donor-acceptor (DA) co-monomers such as 2,6-diaminopurine (DP) into the structure of a polymeric carbon nitride (PCN) backbone using a unique nanostructure co-polymerization strategy and examines its photocatalytic activity performance in the field of photocatalytic CO2 reduction to CO and H2 under visible light irradiation. The as-synthesized samples were successfully analyzed using different characterization methods to explain their electronic and optical properties, crystal phase, microstructure, and their morphology that influenced the performance due to the interactions between the PCN and the DPco-monomer. Based on the density functional theory (DFT) calculation result, pure PCN and CNU-DP15.0 trimers (interpreted as incorporation of the co-monomer at two different positions) were extensively evaluated and exhibited remarkable structural optimization without the inclusion of any symmetry constraints (the non-modified sample derived from urea, named as CNU), and their optical and electronic properties were also manipulated to control occupation of their respective highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). Also, co-polymerization of the donor–acceptor 2,6-diamino-purine co-monomer with PCN influenced the chemical affinities, polarities, and acid–base functions of the PCN, remarkably enhancing the photocatalytic activity for the production of CO and H2 from CO2 by 15.02-fold compared than that of the parental CNU, while also improving the selectivity.