Recently, the most efficient tandem polymer solar cells (PSCs) have used poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as a p-type component of recombination layer (RL). ...However, its undesirable acidic nature, originating from insulating PSS, of PEDOT:PSS drastically reduces the lifetime of PSCs. Here, we demonstrate the efficient and stable tandem PSCs by introducing acid-free self-doped conducting polymer (SCP), combined with zinc oxide nanoparticles (ZnO NPs), as RL for PEDOT:PSS-free tandem PSCs. Moreover, we introduce an innovative and versatile nanocomposite system containing photoactive and p-type conjugated polyelectrolyte (p-CPE) into the tandem fabrication of an ideal self-organized recombination layer. In our new RL, highly conductive SCP facilitates charge transport and recombination process, and p-CPE helps to achieve nearly loss-free charge collection by increasing effective work function of indium tin oxide (ITO) and SCP. Because of the synergistic effect of extremely low electrical resistance, ohmic contact, and pH neutrality, tandem devices with our novel RL performed well, exhibiting a high power conversion efficiency of 10.2% and a prolonged lifetime. These findings provide a new insight for strategic design of RLs using SCPs to achieve efficient and stable tandem PSCs and enable us to review and extend the usefulness of SCPs in various electronics research fields.
To extract charges more efficiently through charge-transporting layers (CTLs), various dopants are necessary. Lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) is the most widely used dopant in ...electron- and hole-transporting layers. However, Li+ ions easily migrate into the perovskite and deteriorate the device performance. To address this issue, several efforts such as introducing a buffer layer have been tried, but the issue is still not fully resolved. Thus it is required to find a simple way without additional treatments. In this work, we propose a simple strategy to use defect-tolerant dopant in CTLs, sodium bis(trifluoromethanesulfonyl)imide (Na-TFSI), to improve both the efficiency and the stability of perovskite solar cells (PSCs). The PSCs with Na-TFSI for both the electron-transport layer and the hole-transport layer show the highest power conversion efficiency up to 22.4%. In addition, the device with Na-TFSI exhibited better long-term operating stability at 45 °C, maintaining >80% of the initial performance even after 500 h of continuous 1 sun illumination.
Realizing industrial-scale, large-area photovoltaic modules without any considerable performance losses compared with the performance of laboratory-scale, small-area perovskite solar cells (PSCs) has ...been a challenge for practical applications of PSCs. Highly sophisticated patterning processes for achieving series connections, typically fabricated using printing or laser-scribing techniques, cause unexpected efficiency drops and require complicated manufacturing processes. We successfully fabricated high-efficiency, large-area PSC modules using a new electrochemical patterning process. The intrinsic ion-conducting features of perovskites enabled us to create metal-filamentary nanoelectrodes to facilitate the monolithic serial interconnections of PSC modules. By fabricating planar-type PSC modules through low-temperature annealing and all-solution processing, we demonstrated a notably high module efficiency of 14.0% for a total area of 9.06 cm
with a high geometric fill factor of 94.1%.
The important but remained issue to be addressed to achieve the mass production of perovskite solar modules include a large‐area fabrication of high‐quality perovskite film with eco‐friendly, viable ...production methods. Although several efforts are made to achieve large‐area fabrication of perovskite, the development of eco‐friendly solvent system, which is precisely designed to be fit to scale‐up methods are still challenging. Herein, this work develops the eco‐friendly solvent/co‐solvent system to produce a high‐quality perovskite layer with a bathing in eco‐friendly antisolvent. The new co‐solvent/additive, methylsulfonylmethane (MSM), efficiently improves the overall solubility and has a suitable binding strength to the perovskite precursor, resulting in a high‐quality perovskite film with antisolvent bathing method in large area. The resultant perovskite solar cells showed high power conversion efficiency of over 24% (in reverse scan), with a good long‐term stability under continuous light illumination or damp‐heat condition. MSM is also beneficial to produce a perovskite layer at low‐temperature or high‐humidity. MSM‐based solvent system is finally applied to large‐area, resulting in highly efficiency perovskite solar modules with PCE of 19.9% (by aperture) or 21.2% (by active area) in reverse scan. These findings contribute to step forward to a mass production of perovskite solar modules with eco‐friendly way.
A rationally designed eco‐friendly solvent system comprising of GBL and new additive, MSM, is newly suggested. Highly efficient over 24% of PCE and stable (over 1000 h) PSCs are presented. New solvent system is more suitable for mass production of PSCs, achieving ≈21% PCE in 25 cm2 solar minimodule, with high tolerance of processing temperature and humidity conditions.
Abstract
A cost‐effective, flexible, and transparent gas barrier has been a main pursuit of research into plastics electronics. However, it is difficult to realize a high‐performance gas barrier on a ...plastic substrate via a solution process at low temperature. Here, by introducing an interfacial photocatalytic reduction between TiO
x
and graphene oxide (GO) films, a solution‐processed and transparent gas barrier film is demonstrated using reduced GO (rGO)/TiO
x
. A dramatic photochemical reduction of GO occurs at the interface between TiO
x
and the GO film under ultraviolet irradiation, which allows the fabrication of dense and uniform gas barrier films via a solution process at temperatures below 100 °C. In addition, the closely packed structure in the rGO film results in a decreased water vapor transmission rate (WVTR) of 0.37 g m
−2
day
−1
even with a thin rGO (<13 nm)/TiO
x
(7 nm) film, leading to a high transmittance of over 80% in the visible range.
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