Enhanced electron transfer dynamics in perylene diimide passivated efficient and stable perovskite solar cells

Abstract

Interfacial engineering for passivating perovskite surface defects and reducing nonradiative recombination loss has been proven to be an effective strategy to fabricate highly efficient and stable perovskite solar cells (PSCs). However, the detailed understanding of the original role of interface materials on the charge‐carriers transfer dynamics of electron transport layer (ETL) remains lacking. Herein, a perylene diimide (PDI) was engineered onto perovskite surfaces to afford passivation of undercoordinated surface defects, which correlates this with the improvement of photovoltaic performance and stability of PSCs. Extensively experimental and theoretical studies reveal that PDI molecule can effectively modulate the surface properties of perovskite film through not only interaction of carbonyl groups in PDI with surface defects but also formation of close‐packed superstructure of PDI onto perovskite surfaces. Consequently, the PDI‐treated PSCs exhibits an increase of power conversion efficiency from 19.52% to 22.24% with an excellent stable device maintaining 95% of its initial value for 900 h in ~45% relative humidity. Importantly, transient absorption spectroscopic measurements further provide an evidence for the origin of the improved photovoltaic performance in PDI‐treated PSCs device, in which the modulation of PDI enhanced the electron transfer across ETL interface more efficiently. Our study provides new insights to understand the effect of interfacial material on the charge‐carrier transfer dynamics in PSCs device.

Slowing the hot‐carrier cooling by an organic small molecule in perovskite solar cells

“…Figure 4C shows the kinetic decay curves of PB features. The TDCA‐treated films show a decay time with a τ rec value of 7.41 μs, which is much higher than that of the control (5.96 μs), which demonstrates the decreased electron–hole recombination in the TDCA‐based perovskite films 15 . Figure 4D exhibits the schematic illustration of the carrier transport process.…”

“…Organic–inorganic hybrid perovskite materials hold great potential for next‐generation photovoltaics due to a range of exceptional optoelectrical properties, such as broad sunlight absorption, tunable bandgap, high charge carrier mobility, and so forth, 1–7 the power conversion efficiency (PCE) of PSCs has reached over 25% 8 . Such remarkable improvement is significantly attributed to the device structure optimization, perovskite defect passivation, perovskite composition engineering, and selective carrier transport materials 9–18 . Despite these progressive advancements, the efficiencies of single‐junction devices still fall behind the Shockley–Queisser (S‐Q) theoretical limit (~33.7%) 19 .…”

“…8 Such remarkable improvement is significantly attributed to the device structure optimization, perovskite defect passivation, perovskite composition engineering, and selective carrier transport materials. [9][10][11][12][13][14][15][16][17][18] Despite these progressive advancements, the efficiencies of single-junction devices still fall behind the Shockley-Queisser (S-Q) theoretical limit ($33.7%). 19 To drive solar cell efficiencies towards S-Q limit value, further research efforts on clearly understanding these fundamental photo-physical processes of device operation are significantly important.…”

Understanding the dopant of hole-transport polymers for efficient inverted perovskite solar cells with high electroluminescence

“…The TA spectra kinetics on nano-to millisecond time scales are generally used to probe the charge recombination dynamics at the interface of perovskite and charge transport layers. 49,50 Therefore, nanosecond transient absorption (ns-TA) spectra were further recorded to study the charge carrier recombination at the HTL/PVK interface. Fig.…”

Catalytic Hot-Electron SERS Analytical Substrates and a Case Study on Graphene Nanocomposite Inspection

“…Energetic electron transfer across an interface between two media is potentially useful in a number of critical technologies such as electric generation, − sensor, − and on-surface chemical transformation. , In particular, the interfacial transfer of hot electrons, each of which stores an energy of ∼1 to 3 eV above the Fermi level at room temperature, , from the electrode surface into the adsorbate can enable various chemical reactions inaccessible via other catalytic processes. − Similarly, such electrochemistry is instrumental in developing charge-transfer (CT) surface-enhanced Raman spectroscopy (SERS), which uses electron transfer between the SERS substrate and the adsorbate to enhance the Raman signal intensity of the adsorbed molecule for efficient chemical detection. − Thus, the ability to realize the parameters determining the transfer of hot charge carriers is fundamentally important to electrode design and utilization.…”