Se-containing inks for the formation of CuInSe2 films without gas-phase selenization

Compound Copper Chalcogenide Nanocrystals

“…NC-based inks have not only been formulated using ternary or quaternary Cu chalcogenide NCs, but also by using metal or oxide NCs, combinations of binary and ternary Cu chalcogenides, and combinations of binary/ternary Cu chalcogenides with salts or molecular precursors. − In spite of the presumed advantage in composition control of NC - based inks, inks based on combinations of binary/ternary NCs (or combinations of NCs with salts) are stated to provide easier control of the final absorber composition. − In this regard, Cao et al used a mixture of Cu 2 SnS 3 , Cu x S, and ZnS NCs to produce 8.5% CZTSSe solar cells, Cai et al used mixtures of metal chloride salts (i.e. CuCl, InCl 3 ) with CuS and In 2 S 3 NCs, coupled with the addition of thiourea, to produce CIS absorbers, and Chesman et al controlled the Ge composition in CZTGeSSe absorbers by mixing CZGeS and CZTS …”

“…This chalcogen replacement has an associated significant volume expansion (14%), which helps film densification and is beneficial to minimize voids and cracks in the film. , Such reactive sintering is also considered to favor the formation of larger crystal domains, when compared with the annealing of sulfide or selenide NCs in an inert atmosphere or in an atmosphere containing the same chalcogen as in the NC . The use of metal NC-based precursors has an even larger associated volume increase with sulfurization or selenization .…”

Facile Exchange of Tightly Bonded L-Type Oleylamine and Diphenylphosphine Ligands on Copper Indium Diselenide Nanocrystals Mediated by Molecular Iodine

“…Nanocrystals made of I–III–VI semiconductors, such as CuInSe 2 , have been of significant interest in the past decade. − Ligand-capped CuInSe 2 nanocrystals can be synthesized as efficient light emitters , or formulated into inks for fabrication of the light-absorbing layer in photovoltaic devices (PVs). − Understanding the physical and chemical relationships between nanocrystals and their organic ligand shell underlies the development of electronic and optoelectronic devices based on these materials . The organic ligands provide colloidal stability, which has enabled the fabrication of PVs on unique substrates like paper and grooves in plastic that cannot withstand high-temperature processing; however, the performance of PVs made with CuInSe 2 nanocrystals without high-temperature selenization has been limited by poor charge transport because of the organic ligands in the film. ,, In the case of PbS nanocrystals, high-performance PVs have been made by modifying the capping ligand layer using various ligand exchange processes with thiols, ammonium salts, and halides. − In one case, addition of I 2 to PbS nanocrystals helped to improve PV device performance .…”

Amino Acid-Based Stabilization of Oxide Nanocrystals in Polar Media: From Insight in Ligand Exchange to Solution 1H NMR Probing of Short-Chained Adsorbates

“…Sulfide or selenide based ligands for example, proved excellent for ligand exchange on metals and metal sulfides, selenides, phosphides or arsenides but showed little affinity towards oxide NCs. [15][16][17][18][19][20][21][22] In addition, ligand exchange schemes 19,[23][24][25] tend to use solvents with high dielectric constants (e.g., formamide, ε = 111 or N-methylformamide, ε = 180) that favor electrostatic stabilization. However, the application of those high-boiling, unstable and toxic solvents is limited.…”

“…Several strategies have already been developed to transfer metal, metal selenide, and metal sulfide NCs to polar solvents, yet these exchange schemes cannot be simply transferred to metal oxide NCs. Sulfide or selenide based ligands for example, proved excellent for ligand exchange on metals and metal sulfides, selenides, phosphides, or arsenides but showed little affinity toward oxide NCs. − In addition, ligand exchange schemes ,− tend to use solvents with high dielectric constants (e.g., formamide, ε = 111 or N -methylformamide, ε = 180) that favor electrostatic stabilization. However, the application of those high-boiling, unstable and toxic solvents is limited.…”