Semi‐Locked Tetrathienylethene as a Building Block for Hole‐Transporting Materials: Toward Efficient and Stable Perovskite Solar Cells

Abstract

The construction of state‐of‐the‐art hole‐transporting materials (HTMs) is challenging regarding the appropriate molecular configuration for simultaneously achieving high morphology uniformity and charge mobility, especially because of the lack of appropriate building blocks. Herein a semi‐locked tetrathienylethene (TTE) serves as a promising building block for HTMs by fine‐tuning molecular planarity. Upon incorporation of four triphenylamine groups, the resulting TTE represents the first hybrid orthogonal and planar conformation, thus leading to the desirable electronic and morphological properties in perovskite solar cells (PSCs). Owing to its high hole mobility, deep lying HOMO level, and excellent thin film quality, the dopant‐free TTE‐based PSCs exhibit a very promising efficiency of over 20 % with long‐term stability, achieving to date the best performances among dopant‐free HTM‐based planar n‐i‐p structured PSCs.

Fluorine‐Substituted Benzotriazole Core Building Block‐Based Highly Efficient Hole‐Transporting Materials for Mesoporous Perovskite Solar Cells

“…However, the complicated synthesis procedures and low yield of Spiro‐OMeTAD make its price very expensive, triggering the researchers over the world to search for/develop efficient and low‐cost alternative HTMs. To date, many alternative HTMs constructed with different conjugated core units, such as phenothiazine, thiophene, phenoxazine, silolothiophene, triazines, and tetraphenylethene, have been reported . Benzotriazole (BTA) is a cheap and commercially available material, which has been widely used in designing sensitizers for dye‐sensitized solar cells by reason of the outstanding electron‐accepting property.…”

Dibenzo[b,d]thiophene‐Cored Hole‐Transport Material with Passivation Effect Enabling the High‐Efficiency Planar p–i–n Perovskite Solar Cells with 83% Fill Factor

“…Hole‐transport materials (HTMs) play an important role in facilitating the transportation of holes from perovskite to the corresponding electrode, and a lot of molecule dopant‐free HTMs have been reported to surpass the high cost and the instability issues of 2,2′,7,7′‐tetrakis( N,N ‐di‐ p ‐methoxyphenylamino)‐9,9′‐spirobifluorene (spiro‐OMeTAD) and poly(bis(4‐phenyl)(2,4,6‐trimethylphenyl)amine) (PTAA), arising from the synthetic complexity and dopants, which are the most widely used and successful HTMs until now . Zhu et al reported a semilocked tetrathienylethene‐containing molecule dopant‐free HTM for the n–i–p pero‐SCs, and the PCE of the best device reached 20% . The highest PCE of the n–i–p pero‐SCs based on molecule dopant‐free HTMs is 21%, achieved by dithieno[3,2 ‐b :2′,3′‐ d ]pyrrol‐cored HTM .…”

Hole‐Boosted Cu(Cr,M)O2 Nanocrystals for All‐Inorganic CsPbBr3 Perovskite Solar Cells

“…[1][2][3][4][5] However,t heir commercialization is still ac hallenge by poor thermal and/or moisture stability in spite of great progresses in either setting blocking layers at interfaces or developing new encapsulation techniques. [6,7] Under longterm illumination and heat attack, the ion migration behavior in hybrid devices is arguable and difficult to completely avoid. [8] Aiming for improved stability,all-inorganic (CsPbX 3 , X = I À ,B r À ,o rC l À )p erovskites free of volatile components by replacing the organic MA + or FA + species with inorganic Cs + have been widely studied for alternative light absorbers.…”