Can we use TDE as an anti-injection technique
The attacker will get the data unencrypted.

The T in TDE stands for "transparent".  The user will never see encrypted data.  The database transparently decrypts it when it is read from disk and transparently encrypts it when writing to disk.  If your application is insecure, TDE doesn't help you plug those application security holes.  You need to fix those in the application (so use bind variables!)