錫鈣鈦礦(Tin Perovskite，簡稱TPsk)具有較鉛鈣鈦礦毒性低、載子遷移率高的特性，且錫鈣鈦礦能隙接近 Shockley-Queisser limit 所需具備的吸光層能隙(~ 1.34 eV ) ，因此錫鈣鈦礦太陽能電池之研究受科學家重視。反式錫鈣鈦礦太陽能電池(Tin Perovskite solar cells，簡稱TPSCs)最常使用的電洞傳遞層(HTL)為PEDOT:PSS，然而PEDOT:PSS膜的work function (-5.15 eV) 與FA0.98EDA0.01SnI3的valence band (-5.84 eV)能階差大，且PEDOT:PSS膜的電洞遷移率僅大約10-4 cm2V-1s-1，仍有改善的空間。本研究嘗試在PEDOT:PSS 中加入硝酸鋅(Zn(NO3)2)作為電洞傳遞層，Zn2+會與PSS-有交互作用，使導電的 PEDOT 鏈與不導電的 PSS 鏈分離並舒張 PEDOT 鏈，增加 PEDOT:PSS 膜的電洞遷移率，有摻雜Zn(NO3)2之PEDOT:PSS膜電洞遷移率由1.710-4 cm2V-1s-1增加至2.8*10-4 cm2V-1s-1 ，使組裝之元件的 Jsc 值可由 22.99 mA/cm2 提升至 25.92 mA/cm2。且摻雜Zn(NO3)2降低PEDOT:PSS膜之work function，使HTL與錫鈣鈦礦層能階差變小，組裝之元件的Voc值由0.55 V增加至0.58 V。以摻雜硝酸鋅之PEDOT:PSS膜作為電洞傳遞層所組裝之元件的光電轉換效率可達 10.60%；而以 PEDOT:PSS 膜作為電洞傳遞層之元件的光電轉換效率僅有8.66%。另外，放置在手套箱中不照光的條件下2200小時後，摻雜硝酸鋅之PEDOT:PSS膜作為電洞傳遞層所組裝之元件的光電轉換效率仍可維持原來的94%，而以 PEDOT:PSS 膜作為電洞傳遞層之元件在相同測試條件下，光電轉換效率僅維持原來的88%。;Tin Perovskite (TPsk) has the characteristics of lower toxicity, higher carrier mobility and ideal band gap which is close to of the light-absorbing layer required by the Shockley-Queisser limit (~ 1.34 eV). These are some reasons that tin perovskite solar cells have attracted the scientists′ attention. The most commonly used hole transport layer (HTL) for Tin Perovskite solar cells (TPSCs) is PEDOT:PSS. However, there is a mismatch energy level between the work function of PEDOT:PSS film (-5.15 eV) and the valence band of TPsk (FA0.98EDA0.01SnI3 (-5.84 eV) used in this study), and the hole mobility of PEDOT:PSS film is only about 10-4 cm2V-1s-1, having a space to improve. In this study, we tried to add zinc nitrate (Zn(NO3)2) into PEDOT:PSS to be a HTL for TPSCs. Zn2+ can interact with the SO3- on PSS, thus separate the more conducting PEDOT chains from the less conducting PSS chains and relax the PEDOT chain simultaneously to increase the hole mobility of the PEDOT:PSS film. The hole mobility of the PEDOT:PSS film doped with Zn(NO3)2 is 2.8×10-4 cm2V-1s-1 (higher than that (1.7×10-4 cm2V-1s-1) of non-doped PEDOT:PSS), and the Jsc value of the corresponding TPSCs is 25.92 mA/cm2 which is also larger than that (22.99 mA/cm2) of the cell based on non-doped PEDOT:PSS HTL. In addition, doping PEDOT:PSS with Zn(NO3)2 reduces the work function of the PEDOT:PSS to match better the valence band of TPsk absorber. As a result, the Voc (0.58 V) of the TPSCs used doped HTL also increases (0.55 V for TPSC based undoped PEDOT:PSS HTL). The power conversion efficiency (PCE) of the devices based on Zn(NO3)2@PS as HTL achieved the highest value of 10.60%, while the PCE of the device based on PEDOT:PSS HTL is only 8.66%. Cell based on Zn(NO3)2@PS HTL can maintain 94% of the initial PCE when the devices were placed in the glove box in dark without packing for 2200 hours, while the PCE of the device based on PEDOT:PSS HTL losts 12% of its initial PCE under the same test condition.
