We present a novel absorber material—NaSbS2—for solar cells. NaSbS2 is formed as an unexpected byproduct in the chemical synthesis of Sb2S3. However, NaSbS2 has many attractive features for a solar material. Here single phase NaSbS2 nanoparticles were synthesized through solution processing. NaSbS2 semiconductor-sensitized solar cells were demonstrated for the first time. The best cell yielded Jsc = 10.76 mA/cm2, Voc = 0.44 V, FF = 48.6%, and efficiency η = 2.30% under 1 sun. At the reduced 0.1 sun, the η increased to 3.18%—a respectable η for a new solar material.

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We present a new ternary semiconductor absorber material -Ag 3 SbS 3 -for solar cells. Ag 3 SbS 3 nanoparticles were grown on mesoporous TiO 2 electrodes using a two-stage successive ionic layer adsorption reaction process. Post annealing transformed the double-layered structure into the Ag 3 SbS 3 phase. The energy gap of the synthesized Ag 3 SbS 3 nanoparticles is estimated to be ∼1.5-1.7 eV. Liquid-junction semiconductor-sensitized solar cells were fabricated from the synthesized nanoparticles using a polysulfide electrolyte. The best cell yielded a short-circuit current density J sc of 11.47 mA/cm 2 , an open-circuit voltage V oc of 0.33 V, a fill factor FF of 38.92%, and a power conversion efficiency η of 1.47% under 1 sun. The external quantum efficiency (EQE) spectrum covered the spectral range of 300-850 nm with a maximal EQE = 80% at λ = 500 nm. At the reduced light intensity of 13% sun, the η increased to 2.18% with J sc = 2.46 mA/cm 2 (which could be normalized to 18.9 mA/cm 2 ). The respectable photovoltaic performance indicates that Ag 3 SbS 3 could be a potential solar absorber material. Semiconductor-sensitized solar cells (SSSCs) have drawn a great deal of attention due to their potential application as a low-cost alternative to Si-based photovoltaic sources. The key component of an SSSC is a mesoporous oxide nanoparticles (usually TiO 2 ) coated with a layer of nanostructured light-absorbing semiconductor. An electrolyte is filled into the porous space of the TiO 2 electrode to complete the charge redox process. Depending on the electrolyte, SSSCs can be classified into two types: solid-state SSSCs (also referred to as extremely thin absorber solar cell-ETA) or liquid-junction SSSCs. The most widely used semiconductor absorber materials are the binary metal chalcolgenides such as CdS, CdSe, PbS, Ag 2 S, Sb 2 S 3 , etc.1-5 These nanostructured semiconductor sensitizers have several advantages including (1) tunable absorption range due to the quantumsize effect, 6 (2) large optical absorption coefficient, 7 and (3) multiple electron-hole pairs produced by a single photon. 8 The highest efficiencies achieved for single-layered binary metal chalcogenide sensitizers are ∼5-7%.9-12 Slightly better efficiencies can be obtained for double-layered core-shell binary sensitizers. [13][14][15] In contrast to binary sensitizers, ternary semiconductors are a relatively unexplored subject. Ternary semiconductors are more difficult to synthesize because there are three elements involved and the stoichiometry must be correct. There are several advantages for ternary semiconductor sensitizers: (1) the energy gap E g can be tuned by varying the ratio among the three elements, (2) large optical absorption coefficients near 10 4 -10 5 cm −1 , and (3) many ternary semiconductors have E g near the optimal E g ∼ 1.4 eV for an optimal solar absorber. 16 However, only a small number of ternary semiconductors, such as CuSbS 2 , Pb-Sb-S, AgInS 2 , AgBiS 2 etc., have been employed as solar absorbers in SSSCs to date (the wi...

The most common structure of a quantum dot-sensitized solar cell (QDSC) employs a metal sulfide counter electrode (CE) combined with a polysulfide electrolyte (S^(2-)/S_n^(2-)). Polyiodide electrolytes (I^-/I_3^-) have an advantage...