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    Effect of bromine doping on the charge transfer, ion migration and stability of the single crystalline MAPb(BrxI1-x)(3) photodetector
    (Royal Soc Chemıstry, 2021) Mahapatra, Apurba; Prochowicz, Daniel; Kruszynska, Joanna; Satapathi, Soumitra; Akın, Seçkin; Kumari, Hemant; Kumar, Pawan
    Organic-inorganic halide perovskites (OIHPs) have emerged as a promising semiconductor for the fabrication of efficient optoelectronic devices such as photodetectors (PDs). Among all the perovskite compositions, the mixed-halide MAPb(BrxI1-x)(3) formulations have gained more attention for photodetection application thanks to their tunable optoelectronic properties and great stability. However, there is still a lack of sufficient understanding of the effect of Br doping on the stability and physical properties of MAPb(BrxI1-x)(3) based PDs. In this work, we prepare a series of MAPb(BrxI1-x)(3) (x = 0, 0.04, 0.08, 0.12, and 0.16) single crystals (SCs) and investigate the influence of the Br content on the crystal structure, charge transport, ion migration, and recombination phenomena. Moreover, self-powered PDs with a structure of Pt/MAPb(BrxI1-x)(3) SC/Pt have been developed, and their optoelectrical properties at different wavelengths of light sources (blue, green, red, and white) have been studied. We found that all the PDs exhibit the highest photoresponse under white light indicating their potential for broad spectrum detection applications. Particularly, the MAPb(Br0.16I0.84)(3) SC PD exhibits the highest responsivity of 2.41 mA W-1 at white light intensity, while the highest detectivity of 15.41 x 10(10) Jones was observed for the MAPb(Br0.12I0.88)(3) SC PD due to the smaller amount of trap states and suppressed ion migration, as proved by impedance spectroscopy. Finally, the photostability and one-year shelf-life stability of the corresponding PDs are demonstrated.
  • Küçük Resim
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    Recent progress of light intensity-modulated small perturbation techniques in perovskite solar cells
    (John Wiley and Sons Inc, 2021) Parikh, Nishi; Narayanan, Saranya; Kumari, Hemant; Prochowicz, Daniel; Kalam, Abul; Satapathi, Soumitra; Akın, Seçkin
    The small perturbation frequency-resolved techniques have been powerful tools in unraveling the kinetic processes governing the operation of perovskite solar cells (PSCs). One such technique is electrochemical impedance spectroscopy (EIS). However, a thorough interpretation of the EIS response of PSCs is still lacking owing to the absence of a uniform electrical equivalent circuit. In this context, intensity-modulated photocurrent/photovoltage spectroscopy (IMPS/IMVS) can be the link between the optical and electrical responses of PSCs and complement the IS technique. In this review, the progress made in interpreting the IMPS/IMVS response of various types of PSCs is summarized and diverse prospects are discussed. First, the basic theory and models present in the literature are discussed. Next, the IMPS/IMVS response of mesoporous and planar PSCs based on various physical parameters is discussed. At last, proposed future prospects for the development of this field are discussed.