p‐Type Carbon Dots for Effective Surface Optimization for Near‐Record‐Efficiency CsPbI₂Br Solar Cells

Abstract

Interface modification to minimize charge recombination and trapping for efficient charge transport is crucial for the performance of perovskite solar cells (PSCs). Herein, functionalized p‐type blue carbon dots (B‐CDs) are ventured as an interface passivation layer to enhance the efficiency and long‐term stability of all‐inorganic CsPbI2Br PSCs. It is found that first the blue carbon dots with abundant NH, CN, CO, and CO functional groups effectively passivate defects by reacting with I− and Pb2+ ions in the perovskite through hydrogen and coordinative bonds. Second, the p‐type B‐CDs modifiers form a P–N junction with the n‐type perovskite to provide efficient pathways for hole transfer and electron blocking. Third, the B‐CDs increase the hydrophobicity of the perovskite film to improve the stability of CsPbI2Br PSCs. With the above advantages, the CsPbI2Br PSC with B‐CDs modification shows an efficiency as high as 16.76%, one of the highest for its type. In addition, the modification renders significant improvement of air and light stability, with 95.33% of the initial PCE retained after storage in the ambient environment for 1000 h. This work demonstrates the great potential of B‐CDs application in perovskite‐based optoelectronic devices.

Record‐Efficiency Flexible Perovskite Solar Cells Enabled by Multifunctional Organic Ions Interface Passivation

“…The relationship between V oc and light intensity is depicted in Figure 4g. The slope of the fitting line was minimized from 1.83 kT/q for the control device to 1.30 kT/q for the HADI-treated device, which means that the trap-assisted surface recombination was obviously suppressed by the HADI treatment, [46] which agrees well with the results obtained by TRPL. In order to further clarify the suppressed recombination, the surface defect density was quantitatively assessed by the space-charge limited current (SCLC) method with the device structure FTO/SnO 2 or HADI-SnO 2 /perovskite/PCBM/Ag (Figure 4h).…”

Stable 24.29%‐Efficiency FA0.85MA0.15PbI3 Perovskite Solar Cells Enabled by Methyl Haloacetate‐Lead Dimer Complex

“…To understand the effect of MHA modification on the morphology of the perovskite film, scanning electron microscopy (SEM) and atomic force microscopy (AFM) characterizations were performed. [54] Top-view SEM images of perovskite films without and with MHA modification are shown in Figure 2a, and the corresponding grain size distributions are summarized in Figure 2b. MClA and MBrA modifications increase the average grain sizes of the perovskite films up to 1020 and 1340 nm, respectively, from 620 nm for the control film.…”

Carbon dot/inorganic nanomaterial composites

“…Therefore, they can be applied to photo-energy conversion devices like solar cells. [145][146][147] Hui et al 148 doped red carbon dots in SnO 2 in the highefficiency electron transport layer and applied it to perovskite solar cells (Fig. 14a).…”