There are two opinions concerning the hour of response on Friday which are likely to be correct:
The first is that it lasts from after ‘Asr until the sun sets, for those who sit and wait for Maghrib, whether that is in the mosque or at home, making du’aa’ to their Lord, whether they are men or women; whoever does that is more deserving of seeing a response to his or her du’aa’. But men should not pray Maghrib or any other prayer at home unless they have a legitimate shar’i excuse, as is well known from the evidence of sharee’ah.
The second is that it lasts from the time when the imaam sits on the minbar to deliver the khutbah on Friday until he finishes the prayer. Du’aa’ at either of these times is deserving of being answered.
These two times are more likely to be the times of response on Friday, because of the saheeh ahaadeeth which indicate that. The hour of response may also be sought at other times of the day. And the bounty of Allaah is great.
Among the moments when response may come to a du’aa’ in all prayers, obligatory and naafil alike, is the moment of sujood (prostration), because the Prophet (peace and blessings of Allaah be upon him) said: “The closest that a person may be to his Lord is when he is prostrating, so say a great deal of du’aa’ in sujood.” (Narrated by Muslim in his Saheeh from the hadeeth of Abu Hurayrah (may Allaah be pleased with him), in al-Salaah, 482). And Muslim (may Allaah have mercy on him) narrated in his Saheeh from Ibn ‘Abbaas (may Allaah be pleased with them both) that the Prophet (peace and blessings of Allaah be upon him) said: “As for rukoo’ (bowing), proclaim the greatness of your Lord in rukoo’ and strive in du’aa’, for you will be more deserving of being responded to.” - Muslim, al-Salaah, 479
Shaykh Ibn Baaz, Majallat al-Buhooth, issue no. 34, p. 142