Ultra-high open-circuit voltage of perovskite solar cells induced by nucleation thermodynamics on rough substrates

Abstract

To obtain high performance CH3NH3PbI3 perovskite solar cells, it is highly important to realise a high open-circuit voltage. Calculation results based on a modified diode model have indicated that a low bare ratio ϕ of the perovskite film is the most important factor determining the open-circuit voltage, where ϕ is defined as the ratio of the projection of the uncovered area of the perovskite film to the apparent area of the total substrate surface. To realise a low ϕ, we investigate the nucleation behaviour of crystals on rough substrates. The analysis results predict that, when CH3NH3PbI3 is deposited on conventional transparent conductive oxide substrates such as fluorine-doped tin oxide, preferential heterogeneous nucleation will occur on the concave regions of the substrate; then, depending on the subsequent growth step, full coverage of the perovskite film at both the macroscopic and microscopic scales is realised. As a result, an ultra-high open-circuit voltage, i.e., 1.20 V, can be achieved in devices using the full coverage CH3NH3PbI3 film. The thermodynamics theory of precipitation nucleation should shed light on solution engineering of thin films.

Facile NiOx Sol-Gel Synthesis Depending on Chain Length of Various Solvents without Catalyst for Efficient Hole Charge Transfer in Perovskite Solar Cells

“…The series resistances ( R s , charge transport resistance) were 7.45 × 10 1 Ω ( R s1 ) and 2.43 × 10 1 Ω ( R s2 ), which were lower in the “NiO x via B-OH” devices than those in the “NiO x via ET-OH” devices. Therefore, this is consistent with the device performance results, which show an improved J sc and PCE (%), as shown in Table 1 [89,90,91].…”

High efficiency planar-type perovskite solar cells with negligible hysteresis using EDTA-complexed SnO2

“…In comparison, the planar-type PSCs with E-SnO 2 ETLs exhibit the best performance. The higher J sc and FF are attributed to the high electron mobility that promotes effective electron extraction, and the larger V oc due to the closer energy level between E-SnO 2 and perovskite 65 . Figure 4b shows the incident-photon-to-charge conversion efficiency (IPCE) and the integrated current of the PSCs based on different ETLs.…”

Revealing the Chemistry between Band Gap and Binding Energy for Lead‐/Tin‐Based Trihalide Perovskite Solar Cell Semiconductors

“…[138c] These are essential factors for the optimization of high solar PCEs. [138] The band gap for the CH 3 NH 3 PbY 3 series is tunable in the 1.50-3.10 eV range. [86,[106][107][108][109] This range has been routinely determined experimentally with ar ange of very common measurementt echniques by diverser esearch groups, which have justifiedu rgency in publication in many high-impactj ournals.…”