Disclosed herein is a modified transposon end sequence comprising a mosaic end sequence, wherein the mosaic end sequence comprises one or more mutation as compared to a wild-type mosaic end sequence, wherein the mutation comprises a substitution with a uracil, an inosine, a ribose, an 8-oxoguanine, a thymine glycol, a modified purine, or a modified pyrimidine. Also disclosed are transposome complexes comprising these modified transposon end sequences and methods of library preparation using these modified transposon end sequences.