UNI-MB - logo
UMNIK - logo
 
E-resources
Full text
Peer reviewed
  • Tuning Solute‐Redistributio...
    Choi, Min‐Jae; Kim, YongJoo; Lim, Hunhee; Alarousu, Erkki; Adhikari, Aniruddha; Shaheen, Basamat S.; Kim, Yong Ho; Mohammed, Omar F.; Sargent, Edward. H.; Kim, Jin Young; Jung, Yeon Sik

    Advanced materials (Weinheim), 08/2019, Volume: 31, Issue: 32
    Journal Article

    Solution‐processed colloidal quantum dots (CQDs) are attractive materials for the realization of low‐cost and efficient optoelectronic devices. Although impressive CQD‐solar‐cell performance has been achieved, the fabrication of CQD films is still limited to laboratory‐scale small areas because of the complicated deposition of CQD inks. Large‐area, uniform deposition of lead sulfide (PbS) CQD inks is successfully realized for photovoltaic device applications by engineering the solute redistribution of CQD droplets. It is shown experimentally and theoretically that the solute‐redistribution dynamics of CQD droplets are highly dependent on the movement of the contact line and on the evaporation kinetics of the solvent. By lowering the friction constant of the contact line and increasing the evaporation rate of the droplets, a uniform deposition of CQD ink in length and width over large areas is realized. By utilizing a spray‐coating process, large‐area (up to 100 cm2) CQD films are fabricated with 3–7% thickness variation on various substrates including glass, indium tin oxide glass, and polyethylene terephthalate. Furthermore, scalable fabrication of CQD solar cells is demonstrated with 100 cm2 CQD films which exhibits a notably high efficiency of 8.10%. A uniform, large‐area deposition of colloidal quantum dot (CQD) ink is demonstrated by tuning the solute‐redistribution dynamics with the aid of an ultrasonic spray coating system. Electronically coupled CQD solids up to 100 cm2 are fabricated, and are further applied to fabricate CQD solar cells that exhibit uniform and up to 8.10% power conversion efficiency over their whole area.