講演情報
[8p-E201-5]N- and P-type PbS Quantum Dots Blended Ink for the Development of Bulk Homojunction Solar Cells
〇(D)Napasuda Wichaiyo1, Yuyao Wei2, Yongge Yang1, Shuzi Hayase1, Takaya Kubo2, Qing Shen1 (1.The Univ. of Electro-Communications, 2.RCAST Univ. of Tokyo)
キーワード：
n- and p-type blended quantum dot、bulk homojunction quantum dot、quantum dot solar cells
Lead sulfide (PbS) colloidal quantum dot solar cells (CQDSCs) are promising photovoltaic technologies owing to their tunable bandgap, solution processability, and low-cost fabrication. However, carrier recombination at quantum dot (QD)/QD interfaces and limited environmental stability remain major challenges restricting further performance improvements. Here, we propose an all-inorganic bulk homojunction (BHJ) strategy by blending n-type and p-type PbS QDs to enhance charge transport, suppress recombination, and improve device stability. Stable p-type PbS QDs were prepared via a solution-phase ligand exchange (SPLE) process using SnI2-mixed lead halide (PbX2; X = I, Br) ligands. By controlling the SnI2 concentration, n-type QD to p-type QD conversion is achieved. The resulting p-type QDs were blended with conventional n-type PbS-PbX2 QDs to form an all-inorganic mixed-charge absorber layer (AL). To the best of our knowledge, this is the first demonstration of an all-inorganic n-type/p-type PbS CQD BHJ fabricated by directly mixing oppositely doped QD inks. The mixed-QD architecture creates distributed nanoscale p-n homojunctions throughout AL, promoting spontaneous charge separation while reducing recombination at QD/QD interfaces. In addition, Sn-derived oxide species provide effective surface passivation and protection against oxidation, leading to enhanced stability. Systematic optimization of n-type/p-type blending ratio resulted in significant photovoltaic improvements compared with conventional PbS QD AL. The optimized BHJ devices achieved power conversion efficiencies exceeding 11%, compared with 9.83% for the control devices. This work establishes a new all-inorganic mixed-charge design framework for CQDSCs and provides a promising route toward efficient and durable QDSC.