Solution Processed Polymer–Inorganic Semiconductor Solar Cells Employing Sb₂S₃ as a Light Harvesting and Electron Transporting Material

Abstract

Hybrid solar cells based upon organic-inorganic semiconductor heterojunctions are currently the subject of signifi cant interest as they incorporate the attractive properties of both organic and inorganic materials, including the ability to tune both the electronic and structural properties over a wide range using solution-based fabrication methods. [1][2][3][4][5][6][7] A confi guration of particular promise is the hybrid inorganic nanocrystalpoly mer bulk heterojunction solar cell. A typical device consists of a photoactive layer composed of a blend of inorganic nanoparticles and a semiconducting polymer, which is sandwiched between two charge-collecting electrodes. The operation of such a system is based upon a photoinduced charge separation reaction at the inorganic-organic semiconductor heterojunction, followed by charge carrier transport and collection at the device electrodes. To date, a variety of inorganic semiconductors have been used in solution processed polymer solar cells including metal oxides, sulfi des and selenides. Metal chalcogenide nanocrystals are especially attractive for use in photovoltaic device applications as they offer the potential to extend the light harvesting capability of the device into the near infrared region of the solar spectrum. For example, impressive solar-light to electrical power conversion effi ciencies have been recently reported for photovoltaic devices based upon CdSe:PCPDTBT ( > 3%) [ 5 , 8 ] and CdS:P3HT nanocomposite fi lms (4.1%). [ 6 ] Key challenges to the design of high-performance hybrid solar cells are (i) the development of new fabrication routes for hybrid thin fi lms that enable the achievement of high yields of charge separation whilst maintaining good electrical connectivity between the inorganic nanocrystals in the photoactive layer and (ii) the development of alternative inorganic electron acceptors that exhibit light harvesting properties superior to the typically used cadmium-based materials. To address challenge (i), we have recently reported a new approach to the fabrication of hybrid metal sulfi de-polymer solar cell photoactive layers, which is based upon the in-situ thermal decomposition of a single source metal xanthate precursor in a polymer fi lm. [ 9 ] The use of metal xanthate (or metal o-alkyl dithiocarbonate) precursors for the in-situ growth of metal sulfi de nanocrystals in polymer fi lms is of particular interest due to their high solubility, low decomposition temperature and the volatility of the side products generated upon thermal decomposition. As such, we have implemented this design strategy in the fabrication of CdS:P3HT and CuInS 2 :polymer nanocomposite fi lms and demonstrated effi cient charge photogeneration at the donor-acceptor heterojunction. [9][10][11] Furthermore, the integration of such photoactive layers into solar cell architectures yielded impressive power conversion effi ciencies approaching 3% under AM1.5 simulated solar illumination. [ 11 ] In this paper, we extend our previous work and report on a bulk hete...

In Situ Synthesis of PbS Nanocrystals in Polymer Thin Films from Lead(II) Xanthate and Dithiocarbamate Complexes: Evidence for Size and Morphology Control

“…4,5 28,29 This synthetic route involves no additional ligands and consequently allows improved contact at polymer-inorganic interfaces and between adjacent nanocrystals, leading to improved charge separation and transport. 31,32 In situ methods are synthetically simpler and have potential for large scale processing, e.g. roll-toroll manufacturing.…”

“…16,17,30 To date, the only metal sulphides to have been synthesised by the decomposition of single source precursors in a polymer film are CdS, 4,5,32,33 , CuInS 2 , 29 ZnS, 34,35 Bi 2 S 3 , 36 and Sb 2 S 3 . 31 Despite an extensive family of single source precursor molecules used for chemical vapour deposition and nanoparticle synthesis, [37][38][39][40][41][42] relatively few have been investigated within a polymer matrix. Of particular note, metal dithiocarbamate complexes have been widely used as precursors for the synthesis of metal sulfide nanocrystals and thin films but have not been tested with the in situ approach.…”

Room-temperature preparation of trisilver-copper-sulfide/polymer based heterojunction thin film for solar cell application

“…Very recently, solution-process for inorganic/organic heterojunction has been extensively studied. Bansal et al [22] prepared Sb 2 S 3 /P3HT inorganic/polymer semiconductor solar cells with Sb 2 S 3 embedding in through a solution process based on an in-situ thermal decomposition of antimony ethyl-xanthate precursor in P3HT polymer film, where the photovoltaic device showed a PCE at 1.29% (AM 1.5 G). Sudip K. Saha and coworkers prepared Cu 2 ZnSnS 4 (CZTS) nanoparticle films to form a CZTS/PCBM pn-heterojunction device, which showed a PCE upto 0.9% [23].…”

Study of surfactant-free lead sulfide nanocrystals-P3HT hybrid polymer solar cells

“…Hybrid polymer solar cells with an absorbing layer consisting of organic-inorganic semiconductor heterojunctions are topic of current research, as they take advantage of both the materials (organic and inorganic), including the ability to tailor their electronic and structural properties over a wide range while retaining the solution processability offered by the polymers [1]. In hybrid solar cells the photoactive layer is sandwiched between two charge-collecting electrodes and the photo excitation taking place mainly in the polymers generates a strongly bound electron-hole pairs (excitons) that can be dissociated at the interface of inorganic nanocrystals (NCs) and conducting polymer.…”