Facile synthesis of CuInS2 nanocrystals “photovoltaic ink” via hot-injection strategy under ambient environment

• Device-grade CIS NCs can be synthesized under ambient environment.
• The optical properties of CIS NCs can be regulated by extending reaction time.
• The Cu-rich samples can be demonstrated to present P-type conductivity.
• An optimum PCE of the corresponding photovoltaic device can reach ~1.53%.

In this letter, oil-dispersed CuInS2 nanocrystals (CIS NCs) “photovoltaic ink” were successfully prepared using hot injection strategy under ambient environment, and different size of nanocrystals could be tailored through extending the reaction time. Series of analytical means were applied to characterize the obtained samples. The relative results revealed that the “copper rich” CIS NCs with a good monodispersity had tetragonal chalcopyrite structure; the size distribution of the samples tended to be widened along with extending reaction time, and the spectral absorption could also be regulated to cover most visible region. Finally, the obtained CIS NCs were sprayed as absorber in photovoltaic devices with the conventional configuration of (Glass/Mo/CIS/CdS/i-ZnO/AZO), and the best device exhibited promising power conversion efficiency of ~1.53% under AM 1.5 g illumination.

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