This review is written to introduce infrared photon detectors based on solution-processable semiconductors. A new generation of solution-processable photon detectors have been reported in the past few decades based on colloidal quantum dots, two-dimensional materials, organics semiconductors, and perovskites. These materials offer sensitivity within the infrared spectral regions and the advantages of ease of fabrication at low temperature, tunable materials properties, mechanical flexibility, scalability to large areas, and compatibility with monolithic integration, rendering them as promising alternatives for infrared sensing when compared to vacuum-processed counterparts that require rigorous lattice matching during integration. This work focuses on infrared detection using disordered semiconductors so as to articulate how the inherent device physics and behaviors are different from conventional crystalline semiconductors. The performance of each material family is summarized in tables, and device designs unique to solution-processed materials, including narrowband photodetectors and pixel-less up-conversion imagers, are highlighted in application prototypes distinct from conventional infrared cameras. We share our perspectives in examining open challenges for the development of solution-processable infrared detectors and comment on recent research directions in our community to leverage the advantages of solutionprocessable materials and advance their implementation in next-generation infrared sensing and imaging applications.among many other areas. Commercially available IR detectors are predominantly based on vacuum-processed inorganic compound semiconductors, which are structurally rigid, brittle, and require fabrication via complex epitaxial growth and costly processes. A new generation of solution-processable semiconductors have been reported in the past few decades including colloidal quantum dots (CQDs) [1,8,9], organic semiconductors (OSCs) [4,7,10,11], perovskites [1,12,13], and two-dimensional (2D) materials [5,14]. These materials offer sensitivity within the IR spectral regions and the advantages of ease of fabrication

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Tuning the parameters to enhance the efficiencies of a novel set of metal free sensitizers for dye sensitized solar cells (DSSC) is carried out by varying the πconjugated spacers that link the donor benzocarbazole to the acceptor cyanoacrylic acid. The molecules are synthesized by different combinations of spacers, namely fluorene-thiophene (BFT), fluorene-furan (BFF), fluorene-phenyl (BFB), and thiophene-phenyl (BTB). The molar extinction coefficients of all the dyes are high which is attributed to benzocarbazole, but it is higher in the dyes in which fluorene is one of the spacers. But interestingly, in the photovoltaic device when the nonfluorene dye BTB is the sensitizer, red-shifted and broader incident photon-to-current efficiency (IPCE) curves are obtained leading to larger short circuit current density, J sc , almost double when compared to BFB-based cell. The efficiency of the device with this dye as the sensitizer is also the highest in this series. The reasons behind these observations are investigated using computational techniques.

Three phenothiazine-based A−π−D−π−D−π−A-type small molecules containing various terminal acceptor units, which act as Lewis base blocks, have been synthesized via an efficient and stepeconomical, direct C−H arylation strategy in the aim toward the development of hole-transporting materials (HTMs) with multifunctional features (such as efficient hole extraction layer, trap passivation layer, and hydrophobic protective layer) for perovskite solar cells (PrSCs). Optical-electrochemical correlation and density functional theory studies reveal that dicyanovinylene acceptor in SGT-421 downshifted the highest occupied molecular orbital (HOMO) level (−5.41 eV), which is more proximal to the valence band (−5.43 eV) of the perovskite, whereas N-methyl rhodanine in SGT-420 and 1,3indanedione (IND) in SGT-422 destabilized the HOMO, leading to an increased interfacial energy-level offset. SGT-421 exhibits superior properties in terms of a sufficiently low-lying HOMO level and favorable energy-level alignment, intrinsic hole mobility, interfacial hole transfer, hydrophobicity, and trap passivation ability over spiro-OMeTAD as a benchmark small-molecule HTM. As envisaged in the design concept, SGT-421-based PrSC not only yields a comparable efficiency of 17.3% to the state-of-art of spiro-OMeTAD (18%), but also demonstrates the enhanced long-term stability compared to the spiro-OMeTAD because of its multifunctional features. More importantly, the synthetic cost of SGT-421 is estimated to be 2.15 times lower than that of spiro-OMeTAD. The proposed design strategy and the study of acceptor−property relationship of HTMs would provide valuable insights into and guidelines for the development of new low-cost and efficient multifunctional HTMs toward the realization of efficient and long-term stable PrSCs.