The addition of cations to TiO 2 photoelectrodes is routinely accepted as a route to enhance the performance of conventional n-i-p solar cells. However, this is typically achieved in multiple steps or by the incorporation of expensive and hydroscopic cationic precursors such as lithium bis(trifluoromethanesulfonyl)imide. In addition, it is often unclear as to whether the incorporation of such cation sources is inducing "doping" or simply transformed into cationic oxides on the surface of the photoelectrodes. In this study, TiO 2 nanofibers were produced through a simple electrospinning technique and modified by introducing lithium and lanthanum precursors in one step. Our results show that the addition of both cations caused minimal substitutional or interstitial doping of TiO 2 .Brunauer-Emmett-Teller measurements showed that lanthanum-treated TiO 2 nanofibers had an increase in surface area, which even exceeded that of TiO 2 P25 nanoparticles. Finally, treated and untreated TiO 2 nanofibers were used in n-i-p solar cells. Photovoltaic characteristics revealed that lanthanum treatment was beneficial, whereas lithium treatment was found to be detrimental to the device performance for both dyesensitized and perovskite solar cells. The results discuss new fundamental understandings for two of the commonly incorporated cationic dopants in TiO 2 photoelectrodes, lithium and lanthanum, and present a significant step forward in advancing the field of materials chemistry for photovoltaics.

Invited for this month's cover picture is the group of Dr. Macdonald from the Department of Chemistry at University College London (UK). The cover picture shows a scanning electron microscopy image of lanthanum‐treated TiO2 nanofibers rendered to show a three‐dimensional representation of the nanostructured solar cell. This work shows that the addition of lithium and lanthanum cations causes minimal substitutional or interstitial doping of TiO2 nanofibers. In a solar cell, photovoltaic characteristics reveal that lanthanum treatment is beneficial, whereas lithium treatment is found to be detrimental to the device performance for both dye‐sensitized and perovskite solar cells. Read the full text of the Article at 10.1002/celc.201900532.

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The authorsh ave identified at ypographicale rror in their manuscript on page 3591. The inter planar spacing for the (101) plane of anatase TiO 2 is stated to be measured as 0.32 nm;h owever,i ts hould be 0.35 nm. The affected sentencef rom the second paragraph of the Results and Discussion section hasb een reproduced below with the corrected text indicated in bold.

The Front Cover shows a scanning electron microscopy image of lanthanum‐treated TiO2 nanofibers rendered to show a three‐dimensional representation of the nanostructured solar cell. This work shows that the addition of lithium and lanthanum cations causes minimal substitutional or interstitial doping of TiO2 nanofibers. More information can be found in the Article by F. Ambroz et al. on page 3590 in Issue 14, 2019 (DOI: 10.1002/celc.201900532).