Self‐Assembly of Hybrid Oxidant POM@Cu‐BTC for Enhanced Efficiency and Long‐Term Stability of Perovskite Solar Cells

Abstract

The controllable oxidation of spiro-OMeTAD and improving the stability of hole-transport materials (HTMs) layer are crucial for good performance and stability of perovskite solar cells (PSCs). Herein, we report an efficient hybrid polyoxometalate@metal-organic framework (POM@MOF) material, [Cu 2 (BTC) 4/3 -(H 2 O) 2 ] 6 [H 3 PMo 12 O 40 ] 2 or POM@Cu-BTC,f or the oxidation of spiro-OMeTAD with Li-TFSI and TBP.W hen POM@Cu-BTC is introduced to the HTM layer as ad opant, the PSCs achieve as uperior fill factor of 0.80 and enhanced power conversion efficiency 21.44 %, as well as improved long-term stability in an ambient atmosphere without encapsulation. The enhanced performance is attributed to the oxidation activity of POM anions and solid-state nanoparticles.T herefore,t his researchpresents afacile way by using hybrid porous materials to accelerate oxidation of spiro-OMeTAD,f urther improving the efficiency and stability of PSCs.Organic-inorganic lead halide perovskites have been demonstrated as an immensely promising photovoltaic material, because of their tunable band gaps,strong optical absorption, as well as low-cost solution-based fabrication processes. [1] In particular,the power conversion efficiency (PCE) of PSCs has advanced rapidly to above 25.2 %, approaching the performance of crystalline silicon solar cells. [2] Even though the efficiencies of PSCs are sufficient for commercialization, their large-scale preparation and practical application are still limited by ap oor long-term stability mainly stem from perovskite or HTM layers. [3] Thestability of perovskite layer may be improved by reinforcing intrinsic stability,employing surface passivation, and using appropriate interlayers. [4] However,e ffectively improving and controlling the stability of the HTM layer are less studied which is also important for whole device.A mong the commonly used HTMs, [5] small organic molecule spiro-OMeTAD,h as wildly proven as the dominant HTM for highly efficient PSCs,mainly ascribing to high solubility and well-matched energy level. [6] However, many practical results testify that pristine spiro-OMeTAD has low conductivity,m oderate hole-mobility and long oxidation time in the order of days,restricting its functionality in highefficiency PSCs. [6c] To solve these problems,lithium bis(trifluoromethanesulfonyl)-imide (Li-TFSI) and 4-tert-butylpyride (TBP) are commonly used bi-dopants to enhance the performance of spiro-OMeTAD-based devices. [7] However,t here are some remaining challenges for these systems. [6c, 8] Specifically, deliquescent and hygroscopic Li-TFSI reacts with water molecules and eventually degrades the HTM and perovskite layers,a nd its ion behavior also strongly affects hysteresis of PSCs. [5b, 9] Therefore,simultaneously accelerating controllable oxidation process of spiro-OMeTAD and improving conductivity,a sw ell as diminishing the influence of Li-TFSI by as imple and efficient strategy will be the key points to the commercialization of PSCs.Polyoxometalates (POMs), at ype of metal oxo-clust...

Mitigation of vacancy with ammonium salt-trapped ZIF-8 capsules for stable perovskite solar cells through simultaneous compensation and loss inhibition

“…To develop these capsules, the encapsulation agents should process porous structure with suitable pores size to contain ammonium salts and release them in suitable situation, and meanwhile, should be hydrophobic to protect the perovskite layer against moisture. In this regard, metalorganic frameworks (MOFs) would be desirable materials due to the characteristic structural and componential controllability, [32][33][34][35][36] hydrophobic property [37][38][39][40] and chemical stability. [41][42][43][44][45] Herein, by harnessing its superior perovskite affinity 34 and hydrophobicity, zeolitic imidazolate framework-8 (ZIF-8) was utilized as an encapsulation agent to generate the sustainedrelease capsule with ammonium iodide trapped inside (Fig.…”

Present and Perspectives of Photoactive Porous Composites Based on Semiconductor Nanocrystals and Metal-Organic Frameworks

“…This section overviews and highlights the photoactive porous composites outlined in Table 1 , according to their application. Most of the examples are photoactive composites based on MHP nanocrystals; however, bulk MHP materials have also been combined with MOF heterojunctions through a sequential solution-processed method (sequential spin coating) to produce perovskite solar cells (PSCs) with improved performance features, power conversion efficiencies, and stabilities (see Section 3.2 , Perovskite Solar Cells) [ 110 , 111 , 112 , 113 , 114 , 115 , 116 , 117 , 118 , 119 ].…”

The crystal structure bis{hexakis(1-methyl-1H-imidazole-κ1N)cobalt(II)} tetrakis(μ3-oxido)-octakis(μ2-oxido)-tetradecaoxido-octamolybdate(VI), C24H36CoMo4N12O13

“…Polyoxometalates (POMs) are metal-oxygen clusters composed of early transition metals in the highest valence state and oxygen atoms [4]. Recently, the organic-inorganic hybrid materials based on POMs have shown application prospects in many fields, such as catalysis [5][6][7], anti-cancer drugs [8], fluorescence [9], energy conversion [10,11].…”