Impact of Monovalent Cation Halide Additives on the Structural and Optoelectronic Properties of CH₃NH₃PbI₃ Perovskite

Abstract

We report the influence of monovalent cation halide additives on the optical, excitonic and electrical properties of CH 3 NH 3 PbI 3 perovskite. Monovalent cation halide with similar ionic radii to Pb 2+ , including Cu + , Na + and Ag + , were added to explore possibility of doping. We observed significant reduction of subbandgap optical absorption and lower energetic disorder along with a shift in the Fermi level of the perovskite in the presence of these cations. The bulk hole mobility of the additive based perovskites as estimated using the space charge limited current method exhibited an increase of up to an order of magnitude compared to the pristine perovskites with a significant decrease in the activation energy.Consequentially, enhancement in the photovoltaic parameters of additive-based solar cells was achieved.We observed an increase in open circuit voltage for AgI (~1.02 vs 0.95 V for the pristine) and photocurrent density for NaI and CuBr based solar cells (≈23 vs 21 mA.cm -2 for the pristine). This enhanced photovoltaic performance could be attributed to the formation of uniform and continuous perovskite film, better conversion and loading of perovskite as well as the enhancement in the bulk charge transport along with a minimization of disorder, pointing towards possible surface passivation.

An Aromatic Diamine Molecule as the A‐Site Solute for Highly Durable and Efficient Perovskite Solar Cells

“…We believe that IZ has not only increased the unit cell volume, but also possibly formed a 2D/3D hybrid structure, resulting in smaller grain sizes when the IZ content is higher than 2.5%. [43a,b] The aromatic structure of IZ is more electrically conductive than linear ones, leading to the enhanced electrical conductivity by the incorporation of IZ, as shown in Figure c (also in Figure S9 in the Supporting Information), which guarantees sufficient charge transport and device operation. Furthermore, ultraviolet photoelectron spectroscopy (UPS) was conducted to understand the electronic structures of IZ‐alloyed MAPbI 3 (Figure d).…”

N‐type Doping of Organic‐Inorganic Hybrid Perovskites Toward High‐Performance Photovoltaic Devices

“…Trivalent metal ions doping (Al 3+ , Bi 3+ , Sb 3+ , In 3+ ) is beneficial to the crystal growth of perovskite films with suppressed microstrain and reduced defects . And monovalent cations of Cu + , Na + , and Ag + were also introduced into the CH 3 NH 3 PbI 3 to tune the morphological, optical, and electrical properties of perovskite films . Although positive effect and great promotion on the progress of PSCs have been achieved by metal cation doping with various valence, the behind nature of doping mechanism especially from the viewpoints of polarity and mobility, is not yet completely clarified.…”

Impact of a Mesoporous Titania–Perovskite Interface on the Performance of Hybrid Organic–Inorganic Perovskite Solar Cells

“…Such an impressive efficiency was achieved due to desired properties including a high absorption coefficient, an ideal/tuneable band-gap and long carrier diffusion lengths as well as photon recycling capability of hybrid organicinorganic perovskite materials [4][5][6][7][8][9][10] . A typical mesoscopic perovskite solar cell (PSC) contains a blocking TiO 2 (bl-TiO 2 ) layer, mesoporous TiO 2 (mp-TiO 2 ), hybrid organic-inorganic perovskite sensitizers, hole transporting material (HTM) and counter electrode (e.g.…”